used in questions for emphasis to press for a definitive answer or to get to the heart of the matter

complete and exhaustive; absolute and in-depth in nature or extent

the end of the year or the period concluding a calendar year

the physical location underneath something

an undercover agent or an insider working within a group

the limit of what one is prepared to accept

bottom of one's heart

seabed; seafloor; bottom of the ocean

to lay a foundation, either literally in construction or figuratively for a project or career

Detroit, Michigan

to lay a foundation or a base for future development

the lowest floor of a building or the bottom layer of a structure

the end of the month

the underlying substance, concrete details, or profound cultural and intellectual heritage

foundation (cosmetics)

in the final analysis; fundamentally; when all is said and done

to buy assets or stocks when prices are perceived to have reached their lowest point or are significantly undervalued

inner strength or self-assurance derived from one's resources, abilities, or support

right in front of one's eyes or clearly visible in a panoramic view

plinth; base; substrate

the bottom part of an object or machine that serves as its primary support

to investigate, probe, or scout to find out the real situation or background information

training in the basic skills or knowledge of the fundamentals

a state of extreme, uncontrolled emotion or excitement, typically used as a loanword in a psychological context

soles of the feet

a photographic negative or plate used to produce prints

sole (of a shoe)

Inside information, background details, or the true state of affairs regarding a person or situation.

answer to a riddle

an underlying basis, such as background knowledge, skills, or health

the physical bottom surface of a pot or pan

having a level or flat underside, often used to describe cookware or vessels

in the final analysis; when all is said and done; fundamentally

in the final analysis; fundamentally or at the root of the matter

the accumulated economic foundation or assets of an organization or state

the key members or backbone of a production crew, organization, or group

the lowest point or most unsuccessful period in a process or state

the bottom of a body of water

Socrates (469-399 BC), ancient Greek philosopher

situated, occurring, or living beneath the surface of the earth; subterranean

in private, secretly, or confidentially; away from public view

to reach a point in a financial venture where profits are equal to the costs

Normandy, France

the cards held in a player's hand that are not visible to others in a game

to take in the whole scene at once; to have a panoramic view

in this world; under the sun; everywhere on earth

in front of one's eyes; right under one's nose