(nautical) The rope connected to and controlling the mainsail.

The principal current in a flow, such as a river or flow of air / (usually with the) That which is common; the norm.

(transitive) To popularize, to normalize, to render mainstream. / (intransitive) To become mainstream.

plural of mainstay

(nautical) The largest (or only) sail on a sailing vessel.

Carried by mains electricity.

(Internet slang, derogatory) spam posted by or on behalf of a mainstream organization

plural of mainstage

(Internet) The primary namespace of a wiki, excluding secondary content such as discussion pages.

plural of mainspring