The acronym for Mountain Equipment Co-op. It is often found on labels on rainjackets, tents, backpacks, thermal clothes (and underclothes), and climbing gear.

When spelled in lowercase, "mec" is the French word (from France much moreso than from Québec) for "guy" or "man". It is used colloquially more than in formal use.

What's up, man? > Qu'est-ce qui s'passe, mec?