What is the meaning of Jer?

Short for jerfalcon.

Ultra-short or reduced vowel in Proto- and Late Common Slavonic (or Slavic), then represented as ъ (back jer [ŭ]) or ь (front jer [ĭ]).

Alternative form of (penis)

Alternative form of (to target, to annoy someone verbally)

second person plural objective caseyou, yourselves

Romanization of 𐌾𐌴𐍂

Latin spelling of жер (jer, land, earth, soil; country; place; distance)

yesterday

Alternative form of ier

second person plural objective caseyou, yourselves

year

that, that one

yer

brambling (Fringilla montifringilla)

because, for (for the reason)

Source: wiktionary.org