What is the meaning of आ?

The second letter and vowel of the Devanagari script.

and

The second vowel in Dhivehi, written in Devanagari script

that

he, this

this

Used to represent the [ɑ~ʌ] sound in Sherpa.

the second vowel of Hindi

inflection of आना (ānā):

1. stem
2. second-person singular intimate present imperative

stem

second-person singular intimate present imperative

The second vowel in Marathi

The second vowel in Nepali.

low-respectful second-person singular imperative of आउनु (āunu)

separated form of आ- (ā-)

up to ... exclusively

With senses determined by the ablative case

1. up to, to, as far as
2. from

up to, to, as far as

from

emphasizing particle after adverbs and nouns

Source: wiktionary.org