An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A place located either at the top of the tube of a large telescope from where one observes or at the back of the tube where instruments are attached to the → Cassegrain focus.

→ observer; → cage.

A written report provided by a visiting astronomer to the observatory describing how his/her observing run has been carried out.

Observing, noun of → observe; → report.

A period of telescope time for observations allocated to a science project.

Observing, noun of → observe; → run.

The long opening in the dome of a telescope through which observation is conducted.

Observing, noun of → observe; → slit.

The state, process, or condition of being or becoming obsolete or outdated and no longer used.

→ obsolete; → -escence.

Becoming obsolete; passing out of use.

→ obsolete; → -escent.

1a) No longer in general use; fallen into disuse.
1b) Biology: (of a living organism) Reduced to a redument, or completely lacking, as compared with a corresponding part in related organisms.
2) To make obsolete by replacing with something newer or better.

From L. obsoletus "grown old, worn-out," p.p. of obsolescere "fall into disuse, be forgotten about, become tarnished," which probably is from ob "away" + an expanded form of solere "to be used to, be accustomed."

Pitâr, from Tabari pitâr "worn out," specifically "rotten tree," pitə-pât "anything worn out or useless," from pit, variant of Pers. pud "worn out, decayed," pusidan/pus- "to rot," cf. Pashto puda, Wakhi pitk "rotten, foul," Kurd. (Kurm.) puc "rotten, useless;" Av. pu- "to stink, rot," akin to Gk. puos, L. pus "pus."

An angle whose measure is greater than 90° and less than 180°.

Obtuse, from M.Fr. obtus (fem. obtuse), from L. obtusus "blunted, dull," p.p. of obtundere "to beat against, make dull," from ob "against" + tundere "to beat," from PIE *(s)tud- "to beat, strike, push, thrust;" → angle.

Zâviyé, → angle; bâz "open," from Mid.Pers. abâz-, apâc-, O.Pers. apa- [pref.] "away, from;" Av. apa- [pref.] "away, from," apaš [adv.] "toward the back;" cf. Skt. ápāñc "situated behind."

1) A particular time, especially as marked by certain circumstances or occurrences.
2) A special or important time, event, ceremony, celebration, etc.
3) A convenient or favorable time, → opportunity, or juncture (Dictionary.com).

M.E. occasioun from O.Fr. ochaison, ocasion "cause, reason, pretext; opportunity," from L. occasionem (nominative occasio) "appropriate time," from occasum, occasus "fall; sunset," p.p. of occidere "fall down, go down," from ob "down, away" + cadere "to fall," → case.

Âkatan, from prefix â- + katan "to fall," cf. Laki: katen "to fall," kat "he/she fell," beko! "fall!" (an insult); katyâ "fallen;" Lori: kat "event, error;" Kurd. (Soriani): kawtin "to fall, befall," kett "fallen;" Kurd. (Kurmanji): da.ketin "to fall down;" Lârestâni: kata "to fall;" Garkuyeyi: darkat, varkat "he/she fell (sudden death);" Gilaki (Langarud, Tâleš): katan "to fall," bakatam "I fell," dakatan "to fall (in a marsh, in a pit)," vakatan "to fall from tiredness, be exhausted," fakatan "to fall from (i.e., lose) reputation;" Tabari: dakətə "fallen," dakətən "to crash down," dakət.gu "stray cow;" Proto-Iranian *kat- "to fall;" cf. L. cadere "to fall," → case, Pers. kâté.

1) Occurring or appearing at irregular or infrequent intervals; occurring now and then.
2) Intended for supplementary use when needed.
3) Pertaining to, arising out of, or intended for the occasion (Dictionary.com).

→ occasion; → -al.

An → impact crater on the → dwarf planet  → Ceres. It has a diameter of about 90 km and a depth of about 4 km.

Named after the Roman agriculture deity of harrowing, a method of leveling soil.

1) To block or stop up (a passage or opening); obstruct. To prevent the passage of.
2) Chem.: To entrap a substance (vapor, gas, liquid, solid) within another (by absorption).

From L. occludere "shut up, close up," from ob "in front of, against" + claudere "to shut, close," → include.

Barkolândan, from bar- "on; upon; against; before; at," → object, + kolândan "to shut," → include.

1) The process of occluding. Something that occludes.
2) Phonetics: Closure at some point in the vocal tract that blocks the flow of air in the production of an oral or nasal stop (TheFreeDictionary.com). 3) Chem.: An absorption process by which a substance adheres strongly to another.

→ occlude; → -tion.

1) Occluding or tending to occlude.
2) Phonetics: An oral or nasal stop. → occlusive consonant.

→ occlude; → -ive.

A → phoneme that is produced following the obstruction of air flow in the → pharynx. The sound arises during the exhalation when the air passage is no longer blocked. English occlusive consonants are [p],[b],[t],[d],[k], and [g]. Same as → stop consonant.

→ occlude; → -ive.

The blocking of light from an astronomical object, such as a star, by another object, such as the Moon or an asteroid, that passes in front of it. Also, the period of time for which this blocking takes place. A → solar eclipse is a particular case of occultation. Determining the moment of stellar occultation by the Moon is used to improve our knowledge of the lunar orbit. Moreover, the occultation of stars by asteroids or planetary satellites provide important data for better measuring the sizes of the occulting bodies. See also → grazing occultation.

M.E. from L. occultation- "a hiding," from occultat(us), p.p. of occultare "to conceal, keep something hidden," frequentative of occulere "to cover over, conceal," from ob "over" + a verb related to celare "to hide," from PIE base *kel- "to conceal."

Forupušân, from foru- "down, downward; below; beneath" (Mid.Pers. frôt "down, downward;" O.Pers. fravata "forward, downward;" cf. Skt. pravát- "a sloping path, the slope of a mountain") + pušân p.pr. of pušândan, accusative of pôšidan, pôš- "to cover; to wear" (related to pust "skin, hide;" Mid.Pers. pôst; O.Pers. pavastā- "thin clay envelope used to protect unbaked clay tablets;" Skt. pavásta- "cover," Proto-Indo-Iranian *pauastā- "cloth").

The act of occupying; the state of being occupied.

Verbal noun of → occupy.

The energy level adopted by a particle, atom, or molecule under quantum mechanical laws.

Occupied, p.p. of → occupy; → level.

To take or fill up (space, time); to take possession and control of a place.

From O.Fr. occuper, from L. occupare "take over, seize, possess, occupy," from ob "over" + intensive form of capere "to grasp, seize, take;" PIE base *kap- "to grasp" (cf. Skt. kapati "two handfuls;" Gk. kaptein "to swallow," O.Ir. cacht "servant-girl," literally "captive;" Goth. haban "have, hold;" O.E. habban "to have, hold," probably Mod.Pers. qâp-, qâpidan "to seize;" Av. haf-, hap- "to keep, observe."

Hagidan, from dialectal Pers.: Šahmirzâdi hâgetan, Saraxsi hagiton, Tabari hâytan, haytan, Semnâni hâtan, Gilaki hâgitan, Lâsgardi agiton, degiton "to occupy;" maybe related to Av. haz- "to occupy;" Skt. sah- "to overcome, be victorious, prevail," saha- "victory," sahate "overcomes, masters;" Gk. ekhein "to have, hold;" PIE base *segh- "to have, to hold."

1) To happen; take place; come to pass.
2) To be found or be present; exist.

M.Fr. occurrer "to happen unexpectedly" or directly from L. occurrere "run to meet, run against, present itself," from ob "against, toward" + currere "to run," → current.

Roxdâdan, literally "to appear," from rox "appearance; aspect; face," variant ruy "face, surface" + dâdan "to give," → event.