Real Dictionary

drill
countable noun: A drill is a tool or machine that you use for making holes.

drill in American English 1
a tool or apparatus for boring holes in wood, metal, stone, teeth, etc.
to bore (a hole) in (something) with or as with a drill
intransitive verb: to pierce or bore something with or as with a drill
noun: a shaftlike tool with two or more cutting edges for making holes in firm materials, esp. by rotation
transitive verb: to pierce or bore a hole in (something)

drill in American English 2
a furrow in which seeds are planted
to sow (seeds) in rows to improve growth and efficiency
intransitive verb: to sow seed in drills
noun: a small furrow made in the soil in which to sow seeds
transitive verb: to sow (seed) in drills

drill in American English 3
a coarse linen or cotton cloth with a diagonal weave, used for work clothes, uniforms, etc.
noun: a strong, twilled cotton fabric

drill in American English 4
a short-tailed, bright-cheeked monkey (Mandrillus leucophaeus) native to W Africa, resembling the mandrill but smaller
noun: a large, baboonlike monkey, Mandrillus leucophaeus, of western Africa, similar to the related mandrill but smaller and less brightly colored: now endangered

drill in British English 1
noun: a rotating tool that is inserted into a drilling machine or tool for boring cylindrical holes
verb: to pierce, bore, or cut (a hole) in (material) with or as if with a drill

drill in British English 2
noun: a machine for planting seeds in rows or depositing fertilizer
verb: to plant (seeds) by means of a drill

drill in British English 3
noun: a hard-wearing twill-weave cotton cloth, used for uniforms, etc

drill in British English 4
noun: an Old World monkey, Mandrillus leucophaeus, of W Africa, related to the mandrill but smaller and less brightly coloured

drill in the Oil and Gas Industry
To drill is to use a tool to make a hole for a well, with the aim of finding oil, gas, or water.