1) Bodypost 1) Timber 2) Watercraft component 
A sternpost is the upright structural member or post at the stern of a (generally wooden) ship or a boat, to which are attached the transoms and the rearmost left corner part of the stern. The sternpost may either be completely vertical or may be tilted or `raked` slightly aft. It rests on or `fays to` the ship`s keel. ...
main member at stern of a ship extending from keel to deck
main member at stern of a ship extending from keel to deck
Vertical timber erected on the aft end of the keel. The rudder is attached to it.
• (n.) A straight piece of timber, or an iron bar or beam, erected on the extremity of the keel to support the rudder, and receive the ends of the planks or plates of the vessel.
Stern'post` noun (Nautical) A straight piece of timber, or an iron bar or beam, erected on the extremity of the keel to support the rudder, and receive the ends of the planks or plates of the vessel. 
[n] - (nautical) the principal upright timber at the stern of a vessel
The rearmost vertical member of a fuselage or hull.
noun (nautical) the principal upright timber at the stern of a vessel
an upright member rising from the after end of a keel; a rudderpost or propeller post. Also called