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

1) A prefix occurring in loanwords from Gk. with the meanings "beside, alongside of, by, beyond."
2) Chemistry: A combining form designating the para (1, 4) position in the benzene ring.
Short for → parahydrogen.

From Gk. para-, from para (preposition) "beside, near, from, against, contrary to," cognate with Av. parā, as below; L. pro "before, for, in favor of," per- "through;" Goth. faur "along;" O.E. for- "off, away."

Pârâ-, parâ-, from O.Pers. parā (adv.) "along; forth;" Av. parā (adv.) "at first, in the first place; in former times, formerly;" also "away, aside;" cf. Skt. purā: "before, formerly;" cognate with Gk. para, as above.

The → water molecule in which the → nuclear spins of the constituent → hydrogen atoms are → antiparallel (→ parahydrogen). See also: → ortho-water.

→ para-; → water.