What is the meaning of Mga?

ISO 639-2 & ISO 639-3 language code for Middle Irish.

used to pluralize nouns: -s, -es

pluralizing indicator: -s, -es

about; approximately; around

used to pluralize nouns: -s, -es;

used to pluralize nouns: -s, -es

approximately; around; about

Source: wiktionary.org