(physics, astronomy) gravitational radiation, in the megahertz to gigahertz region, which is proposed to have been produced by the Big Bang or by the collision of massive astronomical objects or artificially in the laboratory. Gravitational waves having frequencies higher than 100 kHz.

Of or pertaining to high frequency sound or other radiation. / Occurring or doing something very frequently.

Alternative spelling of hideout

plural of high school

(of a person, idiomatic) Old, past the prime of life.

Having a great risk.

(uncountable) Any or all of several formats of television system having a higher resolution than traditional ones / (countable) A television set that employs such a system

(athletics) An athlete who competes in the high jump.

(archaic) Of high social standing as a result of having been born a member of an upper-level social class.

(US) A light-skinned black person.