What is the meaning of ا?

The first letter of the Acehnese alphabet, written in the Arabic script.

Although usually considered to be the first letter of the Arabic alphabet, the small hamza (ء (ʔ)) that sits on top of أ (ʔ) is really the first letter of the Arabic alphabet, and the tall column is its bearer. This entry only deals with the lower part, the bearer, which is called أَلِف (ʔalif) and, without the hamza, is used to lengthen a preceding a.

The first numeral symbol of the Arabic alphabet (traditional abjad order, used for list numbering), written in the Arabic script; followed by ب (b).

The first letter of the Balti alphabet, written in the Arabic script.

The first letter of the Burushaski alphabet, written in the Arabic script.

they; third-person plural pronoun

The first letter of the Khowar alphabet, written in the Arabic script; followed by آ.

The first letter of the Kyrgyz alphabet, written in the Arabic script.

alternative spelling of ـها when it is not pronounced as “-ha”

A letter of the Old Ruthenian alphabet, written in the Arabic script.

The first letter of the Pahari-Potwari alphabet, written in the Shahmukhi script; followed by ب (b).

The first letter of the Xiao'erjing abjad, written in the Arabic script.

الف (álif): the first letter of the Arabic alphabet, named Alif, Alef or Aleph

The first letter of the Lisan ud-Dawat abjad, written in the Arabic script; followed by ب.

The first letter of the Kashmiri alphabet, written in the Arabic script; followed by ب.

The first letter of the Kazakh alphabet, written in the Arabic script; followed by ب.

The first letter of the Malay alphabet, written in the Arabic script.

The first letter of the Pashto alphabet, written in the Arabic script; followed by ب.

The first letter of the Persian alphabet, called اَلِف (alef) and written in the Arabic script; followed by ب.

from, since

The first letter of the Punjabi alphabet, written in the Shahmukhi script; followed by ب (b).

The first letter of the Sindhi alphabet, written in the Arabic script; followed by ب.

The first letter of the Urdu alphabet, written in the Arabic script; followed by ب.

A negating prefix. non-, un-, a-, an-, etc.

The first letter of the Yoruba alphabet, written in the Arabic script; followed by ب.

Source: wiktionary.org