(See also ESSENCE.)

down to bedrock Down to basics or fundamentals; down to the essentials. Bedrock is literally a hard, solid layer of rock underlying the upper strata of soil or other rock. Thus, by extension, it is any foundation or basis. Used literally as early as 1850 in Nelson Kingsley’s Diary, the phrase appeared in its figurative sense by 1869 in Our New West by Samuel Bowles.

get down to brass tacks To get down to business; to get down to the essential or fundamental issues. Although the precise origin is unknown, this expression is said to have been originally a nautical phrase referring to the brass nails exposed during the cleaning of the hulls on early sailing ships. Brass was used to resist the corrosion of sea water in fastening metal sheathing to the hull. The phrase appeared as early as 1897 in Liars by H. A. Jones.

meat-and-potatoes Basic, fundamental, essential, main. Meat and potatoes have long been the basic ingredients of a traditional hearty meal.

nitty-gritty The heart of a matter. This American slang term first appeared in 1963 as part of the Black militant slogan get down to the nitty-gritty.

The phrase is conjectured to be an oblique reference to the small hard-to-remove nits or lice that are often found attached to the hair and scalp of poor ghetto-dwellers because of unclean living conditions.

nuts and bolts Basics, brass tacks, the nitty-gritty, the heart of the matter. Since literal nuts and bolts are essential parts of virtually any machine, it is only logical that figuratively they symbolize the essence or core of something, the practical basics. This expression, apparently of fairly recent coinage, dates from at least 1960.