dig

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

• intransitive verb To break up, turn over, or remove (earth or sand, for example), as with a shovel, spade, or snout, or with claws, paws or hands.
• intransitive verb To make or form by removing earth or other material.
• intransitive verb To prepare (soil) by loosening or cultivating.
• intransitive verb To obtain or unearth by digging.
• intransitive verb To obtain or find by an action similar to digging.
• intransitive verb To learn or discover by careful research or investigation.
• intransitive verb To force down and into something; thrust.
• intransitive verb To poke or prod.
• intransitive verb Sports To strike or redirect (a ball) just before it hits the ground, keeping it in play, as in tennis or volleyball.
• intransitive verb To understand fully.
• intransitive verb To like, enjoy, or appreciate.
• intransitive verb To take notice of.
• intransitive verb To loosen, turn over, or remove earth or other material.
• intransitive verb To make one's way by or as if by pushing aside or removing material.
• intransitive verb Slang To have understanding.
• noun A poke or thrust.
• noun A sarcastic, taunting remark; a gibe.
• noun An archaeological excavation.
• noun Sports An act or an instance of digging a ball.
• noun Lodgings.
• idiom (dig in (one's) heels) To resist opposition stubbornly; refuse to yield or compromise.
• idiom Slang (dig it out) To run as fast as one can, especially as a base runner in baseball.

from The Century Dictionary.

• To make a ditch or other excavation; turn up or throw out earth or other material, as in making a ditch or channel or in tilling: as, to dig in the field; to dig to the bottom of something.
• To study hard; give much time to study; grind.
• To excavate; make a passage through or into, or remove, by loosening and taking away material: usually followed by an adverb: as, to dig up the ground; to dig out a choked tunnel.
• To form by excavation; make by digging: as, to dig a tunnel, a well, a mine, etc.; to dig one's way out.
• To break up and turn over piecemeal, as a portion of ground: as, to dig a garden with a spade; a hog digs the ground with his snout.
• To excavate a passage or tunnel for; make a way of escape for by digging: as, he dug himself out of prison.
• To obtain or remove by excavation; figuratively, to find or discover by effort or search; get by close attention or investigation: often followed by up or out: as, to dig potatoes; to dig or dig out ore; to dig up old records; to dig out a lesson.
• To cause to penetrate; thrust or force in: followed by into: as, he dug his spurs into his horse's flanks; he dug his heel into the ground.
• noun A thrust; a punch; a poke: as, a dig in the ribs: often used figuratively of sarcasm and criticism.
• noun A diligent or plodding student.

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

• transitive verb To turn up, or delve in, (earth) with a spade or a hoe; to open, loosen, or break up (the soil) with a spade, or other sharp instrument; to pierce, open, or loosen, as if with a spade.
• transitive verb To get by digging.
• transitive verb To hollow out, as a well; to form, as a ditch, by removing earth; to excavate.
• transitive verb colloq. To thrust; to poke.
• transitive verb colloq., colloq. To like; enjoy; admire.
• transitive verb to undermine and cause to fall by digging; as, to dig down a wall.
• transitive verb to get out or obtain by digging. The preposition is often omitted; as, the men are digging coal, digging iron ore, digging potatoes.
• transitive verb To entrench oneself so as to give stronger resistance; -- used of warfare or negotiating situations.