Hemisphere

HEM-ih-sfeer /ˈhɛmɪsfɪər/
nounB2SATTOEFLIELTS
formalscientific

A half of a sphere; a half of the earth, especially one of the halves into which the earth is divided by the equator or a meridian; (in anatomy) a half of the cerebrum or cerebellum.

Most commonly refers to the left or right half of the brain's cerebrum, each with specialized functions.

The story behind the word. The word 'hemisphere' comes from the Greek 'hemispherion,' meaning 'half-sphere.' It combines 'hemi-' (meaning 'half') and 'sphaira' (meaning 'ball' or 'sphere'). It entered English in the late 14th century, initially referring to half of the celestial or terrestrial globe, and later adopted to describe the halves of the brain.

Word relationships

  • half-sphere: A literal description, but 'hemisphere' is the standard term.

Collocations

  • left hemisphere
  • right hemisphere
  • cerebral hemisphere
  • northern hemisphere

Example sentences

  • "The human brain is divided into two main hemispheres, the left and the right, connected by the corpus callosum." Brain anatomy
  • "Most of Europe is located in the Northern Hemisphere." Geography lesson

Memory hook

HEMISPHERE is 'HEMI-sphere' – half of a sphere, like half of the brain. Half sphere

When not to use

Do not use 'hemisphere' to refer to a general section or part; it specifically means half of a spherical or roughly spherical object.

Fun facts

  • The two cerebral hemispheres are not perfectly symmetrical; there are subtle anatomical and functional differences.
  • The idea of 'left-brained' (logical) vs. 'right-brained' (creative) is a popular oversimplification of how the hemispheres function.

Related words

Cerebral, Cortex

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