posterior

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Located behind a part or toward the rear of a structure.
• adjective Relating to the caudal end of the body in quadrupeds or the back of the body in humans and other primates.
• adjective Botany Next to or facing the main stem or axis.
• adjective Coming after in order; following.
• adjective Following in time; subsequent.
• noun The buttocks.

from The Century Dictionary.

• Later in position in a series or course of action; coming after.
• Especially, later or subsequent in time: opposed to prior.
• Situated behind; hinder: opposed to anterior.
• In botany, situated on the side nearest the axis; superior: said of the parts of an axillary flower. Compare anterior.
• noun The hinder part; in the plural, the hinder parts of the body of man or any animal.
• noun plural The latter part.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Later in time; hence, later in the order of proceeding or moving; coming after; -- opposed to prior.
• adjective Situated behind; hinder; -- opposed to anterior.
• adjective (Anat.) At or toward the caudal extremity; caudal; -- in human anatomy often used for dorsal.
• adjective (Bot.) On the side next the axis of inflorescence; -- said of an axillary flower.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Located behind, or towards the rear of an object.
• adjective Following in order or in time.
• adjective anatomy Nearer the back end; nearer the caudal end of the body in quadrupeds or the dorsal end in bipeds.
• adjective botany Next to, or facing the main stem or axis.
• noun euphemistic The buttocks.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the fleshy part of the human body that you sit on
• adjective located at or near or behind a part or near the end of a structure
• noun a tooth situated at the back of the mouth
• adjective coming at a subsequent time or stage