(US, slang) The primary woman that a man is romantically involved with / (by extension) Something or someone of great importance.

With all one's strength; as hard as one can.

All one's strength.

(obsolete) A venture which stands the best likelihood of success; a risk; fortune (of a person, country etc.).

plural of main house

The largest house on an estate or parcel of land.

(historical) The dagger held in the left hand, while the rapier is held in the right; used to parry thrusts of the adversary's rapier.

plural of main building

plural of main drag

plural of main-deck