Columbia Encyclopedia

Search results

500 results found

biceps

(Encyclopedia)CE5 Biceps of arm biceps bīˈsĕps [key], any muscle having two heads, or fixed ends of attachment, notably the biceps brachii at the front of the upper arm and the biceps femoris in the thigh. O...

borage

(Encyclopedia)CE5 Forget-me-not, Myosotis virginica, a member of the borage family borage bŏrˈəj, bŭrˈ– [key], common name for the Boraginaceae, a family of widely distributed herbs and some tropical shr...

adaptive radiation

(Encyclopedia)CE5 Adaptive radiation in Hawaiian honey-creepers adaptive radiation, in biology, the evolution of an ancestral species, which was adapted to a particular way of life, into many diverse species, e...

semaphore

(Encyclopedia)CE5 Positions of a railroad semaphore: (A) clear, (B) caution, (C) stop semaphore sĕmˈəfôrˌ [key], device for the visible transmission of messages. The marine semaphore, used by day between s...

geologic timescale

(Encyclopedia)CE5 geologic timescale, a chronological scale of earth's history used to measure the relative or absolute age of any part of geologic time. Of the numerous timescales, the most common is based on g...

quadratic

(Encyclopedia)quadratic, mathematical expression of the second degree in one or more unknowns (see polynomial). The general quadratic in one unknown has the form ax2+bx+c, where a, b, and c are constants and x is t...

anthracene

(Encyclopedia)CE5 anthracene ănˈthrəsēn [key], C14H10, solid organic compound derived from coal tar. It melts at 218℃ and boils at 354℃. When pure it is colorless and has a violet fluorescence; it darken...

ketone

(Encyclopedia)CE5 Ketones ketone kēˈtōn [key], any of a class of organic compounds that contain the carbonyl group, C=O, and in which the carbonyl group is bonded only to carbon atoms. The general formula fo...

leaf

(Encyclopedia)CE5 Microscopic cross section of the leaf blade CE5 Types of leaves leaf, chief food-manufacturing organ of a plant, a lateral outgrowth of the growing point of stem. The typical leaf consist...

semiconductor

(Encyclopedia)CE5 N-type and P-type crystals: In a pure silicon crystal each silicon atom (Si) is surrounded by four valence electrons. In the N-doped semiconductor, illustrated in the left-hand figure, some sil...