An Etymological Dictionary of Astronomy and Astrophysics

1. Logic: Relating to or involving inductive reasoning from particular facts or effects to a general principle (dictionary.com).
   

2. Logic: Derived from or requiring evidence for its validation or support; empirical; open to revision (dictionary.com). → a priori.

Etymology (EN): L., literally “from what comes after,” from posterior “after, later, behind,” comparative of posterus “coming after, subsequent,” from post “after,” → post-.

Etymology (PE): Afdom “the last,” Dehxodâ: afdom “last, end;” Mid.Pers. abdom, apdom; from Proto-Ir. *apatama- superlative of *apa- “away from, from;” cf. Av. apəma- “the last, the most distant;” Skt. apamá-.

1. Logic: Relating to or involving inductive reasoning from particular facts or effects to a general principle (dictionary.com).
   

2. Logic: Derived from or requiring evidence for its validation or support; empirical; open to revision (dictionary.com). → a priori.

Etymology (EN): L., literally “from what comes after,” from posterior “after, later, behind,” comparative of posterus “coming after, subsequent,” from post “after,” → post-.

Etymology (PE): Afdom “the last,” Dehxodâ: afdom “last, end;” Mid.Pers. abdom, apdom; from Proto-Ir. *apatama- superlative of *apa- “away from, from;” cf. Av. apəma- “the last, the most distant;” Skt. apamá-.

1. Logic: Relating to or involving deductive reasoning from a general principle to the expected facts or effects (dictionary.com).
   

2. Logic: Known to be true independently of or in advance of experience of the subject matter; requiring no evidence for its validation or support (dictionary.com). → a posteriori.

Etymology (EN): L., literally “from what comes first,” from priori, ablative of prior
“former, previous, first,” → per-.

Etymology (PE): Partom “the first,” Dehxodâ: fardom; Mid.Pers. fradom, fratom, pratom; O.Pers. fratama-; Av. fratəma- (Skt. prathama- “earliest, initial, first”) superlative of fra- “before, forward, forth,” cognate with Gk. and L. → pro-.

1. Logic: Relating to or involving deductive reasoning from a general principle to the expected facts or effects (dictionary.com).
   

2. Logic: Known to be true independently of or in advance of experience of the subject matter; requiring no evidence for its validation or support (dictionary.com). → a posteriori.

Etymology (EN): L., literally “from what comes first,” from priori, ablative of prior
“former, previous, first,” → per-.

Etymology (PE): Partom “the first,” Dehxodâ: fardom; Mid.Pers. fradom, fratom, pratom; O.Pers. fratama-; Av. fratəma- (Skt. prathama- “earliest, initial, first”) superlative of fra- “before, forward, forth,” cognate with Gk. and L. → pro-.

One of → Saturn’s rings, lying beyond the → B ring at 122,170 km from the center of Saturn, with a width of 14,600 km.

See also: → ring.

One of → Saturn’s rings, lying beyond the → B ring at 122,170 km from the center of Saturn, with a width of 14,600 km.

See also: → ring.

A star whose spectrum shows strong hydrogen → Balmer lines accompanied by many faint to moderately strong metallic lines. In contrast to B and O stars, the lines of
He I and He II are absent. Their surface temperature ranges from 7,500 to 10,000 K. The main metallic lines seen in A-type stars are those of
Fe I and Fe II, Cr I and II, Ti I and II, and account for about two-thirds of all lines. Some famous examples of A star are: → Sirius; → Deneb, → Altair, and → Vega. Also known as A-type star.

See also: A, letter of alphabet used in the → Harvard classification; → type; → star.

A star whose spectrum shows strong hydrogen → Balmer lines accompanied by many faint to moderately strong metallic lines. In contrast to B and O stars, the lines of
He I and He II are absent. Their surface temperature ranges from 7,500 to 10,000 K. The main metallic lines seen in A-type stars are those of
Fe I and Fe II, Cr I and II, Ti I and II, and account for about two-thirds of all lines. Some famous examples of A star are: → Sirius; → Deneb, → Altair, and → Vega. Also known as A-type star.

See also: A, letter of alphabet used in the → Harvard classification; → type; → star.

Prefix meaning “not.”

Etymology (EN): From Gk. a-, an- “not,” compare with O.Pers./Av. a-, an- “not, without,” Skt. a-, an- “not,” L. in-, a variant of PIE *ne- “not”.

Etymology (PE): A-, an-, from O.Pers./Av. negation prefix appearing before consonants and vowels respectively.
A couple of examples in Mod.Pers.: amordâd “immortality, name of the fifth month in the Iranian calendar,” anušé; “fortunate, happy,” anirani “non Iranian,” âhu “vice, defect,” âsoqdé “unburnt, half-burnt wood.”
Bi- privative prefix, from Mid.Pers. abi-, O.Pers. *apaiy-, Av. apa-.
Nâ- negation prefix “not, no,” Mid.Pers. ne, O.Pers. naiy, Av. na-, (particle of negation noit), Skt. na-, (ned), Gk. né- “not,” L. ne-, in-, un-, PIE *ne-.

Prefix meaning “not.”

Etymology (EN): From Gk. a-, an- “not,” compare with O.Pers./Av. a-, an- “not, without,” Skt. a-, an- “not,” L. in-, a variant of PIE *ne- “not”.

Etymology (PE): A-, an-, from O.Pers./Av. negation prefix appearing before consonants and vowels respectively.
A couple of examples in Mod.Pers.: amordâd “immortality, name of the fifth month in the Iranian calendar,” anušé; “fortunate, happy,” anirani “non Iranian,” âhu “vice, defect,” âsoqdé “unburnt, half-burnt wood.”
Bi- privative prefix, from Mid.Pers. abi-, O.Pers. *apaiy-, Av. apa-.
Nâ- negation prefix “not, no,” Mid.Pers. ne, O.Pers. naiy, Av. na-, (particle of negation noit), Skt. na-, (ned), Gk. né- “not,” L. ne-, in-, un-, PIE *ne-.

Same as → A star.

See also: A, letter of alphabet used in the → Harvard classification; → type; → star.

Same as → A star.

See also: A, letter of alphabet used in the → Harvard classification; → type; → star.

→ 1I/‘Oumuamua.

See also: → asteroid designation.

→ 1I/‘Oumuamua.

See also: → asteroid designation.