Russian

Preposition

обо • ‎(obo)

1. (+ prepositional case): about, of, on

   обо мне‎ ― obo mne ― about me

   обо всех‎ ― obo vsex ― about everybody

2. (+ accusative case): against, upon

   обо что-нибудь‎ ― obo što-nibudʹ ― upon something

Usage notes

The form обо is used before мне, что (and compound words beginning with чтo); also along with о before inflected forms of все, всё, весь. In most cases, use о ‎(o) or об ‎(ob) instead.