preposition

1. Initialism of with reference to.

preposition

1. Concerning; about.

   “I am writing with regard to the advertisement that you placed in last week's Daily News.”

Synonyms: WRT, with respect to, in regard to

preposition

1. Regarding; concerning; pertaining to.

2. Taking as the independent variable.

   “To calculate acceleration, you need to differentiate velocity with respect to time.”

Synonyms: anent, as regards, in respect of, in terms of, with regard to