What is the meaning of Ob?

a halfpenny

an objection

the obese gene

observation

every other/second

Introduces an indirect question, a doubt. if, whether.

if, in case

on account of [with genitive or dative]

over, above, on [with dative]

Introduces an indirect question, a doubt. if, whether.

alternative form of of

alternative form of aub

two

in the direction of, to, towards

on account of, according to, because of, due to, for (the purpose of)

against; facing

if, whether

alternative form of ab

I

Source: wiktionary.org