Dictionary.com

Meta comes from the Greek prefix and preposition meta, which means “after” or “beyond.” When combined with words in English, meta- often signifies “change” or “alteration” as in the words metamorphic or metabolic.

[…]

Meta-, here, suggests “transcending” or “overarching,” helping it become a synonym for “self-referential” by the 1980s in postmodernism and popular culture

Meta is a monthly gathering where Tarlab discusses Tarlab in order to develop and enhance the lab, discuss buying new things (or selling old) etc. Tarlab Meta happens in the start of every months first open day. Some spaces call these ‘community meetings’.