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

1a) The act or state of touching or being in immediate proximity, as in a → contact binary.
1b) One of the instances when the apparent position of the edges of the Sun and the Moon cross one another during an eclipse. They are designated as the → first contact, → second contact, → third contact, and → fourth contact. See also → contact binary, → last contact.
2a) (v. intr.) To be in or come into contact.
2b) (v.tr.) To bring or put in contact.

From L. contactus "a touching," p.p. of contingere "to touch," from → com- "together" + tangere "to touch."

Parmâs "contact, touching," stem of parmâsidan "to touch, feel," from *pari-mars-, from Indo-Iranian *pari- "around" (O.Pers. pariy "around, about," Av. pairi "around, over," Skt. pari) + *mars- "to touch; to wipe, rub," Mid.Pers. marz "contact, touching," marzitan "to touch," Mod.Pers. mâlidan "to rub," Av. marəz- "to rub, wipe," marəza- "border, district," Skt. mrś- "to touch," mrśáti; L. mulceo "to caress," margo "edge" (Fr. marge "margin"); P.Gmc. *marko; Ger. Mark; E. mark, margin.

1) A → binary star system in which the two → components are so close that they exchange gases in a complex manner. Their overlapping → gravitational fields form a "peanut" shaped → equipotential surface.
2) Two roughly similar-sized asteroids or cometary nuclei resting on one another, presumably after coming together very gently. Examples are → Comet 67P/Churyumov-Gerasimenko and the asteroid → (486958) 2014 MU69.

→ contact; → binary.

1) The beginning of a → solar eclipse when the eastern part of the lunar limb touches the western limb of the Sun, marking the beginning of an eclipse.
2) For a → lunar eclipse, the moment when the eastern limb of the Moon is the first to enter the Earth's shadow.

→ first; → contact.

The end of a solar eclipse marked by the disk of the Moon completely passing away from the disk of the Sun.

From M.E. fourthe, O.E. féowertha, from four, from O.E. feower, from P.Gmc. *petwor- (cf. Du. and Ger. vier, O.N. fjorir, Dan. fire, Sw. fyra), from PIE *qwetwor (cf. Mod.Pers. cahâr, Av. caθwar-, catur-, Skt. catvarah, Gk. tessares, L. quattuor) + -th a suffix used in the formation of ordinal numbers, from M.E. -the, -te, O.E. -tha, -the; cf. O.N. -thi, -di; L. -tus; Gk -tos; → contact.

Parmâs, → contact; cahârom cardinal form from cahâr "four," cognate with E. four, as above.

Same as → fourth contact at an eclipse.

→ last; → contact.

The beginning of the total phase of a solar eclipse when the leading edge of the Moon touches the eastern edge of the Sun completely obscuring the Sun.

→ second; → contact.

The end of the total phase of a solar eclipse marked by the trailing edge of the Moon first revealing the Sun.

→ third; → contact.