An explosive device sent through the post; a letter bomb or parcel bomb.

To send a mail bomb (of either sense).

Maidenhair (Adiantum spp.).

(uncountable) A woman's pubic hair. / Either of two species of genus Adiantum of fern with delicate, hair-like stalks, especially Adiantum capillus-veneris.

A collection point for mail intended for onward delivery, a secure box or receptacle for this purpose. / A delivery point for mail, a box, compartment or slot for this purpose.

(horology) The principal spring of a clockwork mechanism, which drives it by uncoiling. / (figuratively) The most important reason for, or element of, something.

plural of main line

Alternative spelling of mainline

Normal, principal or standard. / (rail transport) Of or pertaining to the principal route or line of a railway.

(slang) To inject (a drug) directly into a vein. / (by extension, informal, transitive) To consume voraciously.