What is the meaning of ə?

a reduced mid-central vowel, undefined for rounding.

[ə]-coloring or a weak, fleeting, epenthetic or echo [ə].

a reduced e vowel.

an extremely short or fleeting ə.

schwa, e.g. \sō′fə\ for sofa.

The seventh letter of the Azerbaijani alphabet, written in the Latin script.

A letter of the Comox alphabet, written in the Latin script.

A letter of the Fe'fe' alphabet, written in the Latin script.

A letter of the Halkomelem alphabet, written in the Latin script.

A letter of the Kwak'wala alphabet, written in the Latin script.

The eleventh letter of the Lushootseed alphabet, written in the Latin script.

A letter of the Maskelynes alphabet, written in the Latin script.

A letter of the Okanagan alphabet, written in the Latin script; ⟨ə́⟩ counts as a distinct letter.

A letter of the Osage alphabet, written in the Latin script.

Phonetic transcription of sounds [ə́, ə̀].

A letter of the Wakhi alphabet, written in the Latin script.

A letter of Uyghur New Script of China, written in the Latin script.

Source: wiktionary.org