(chemistry) Any one of a number of compounds that exhibit optical isomerism.

(organic chemistry) An unsaturated hydrocarbon, C₅H₈, that is readily polymerized; natural rubber (caoutchouc) is cis-1,4-polyisoprene, and trans-1,4-polyisoprene is present in gutta-percha and balata; it is the structural basis for the terpenes.

That is the way things happen / Certain things cannot be changed, helped or improved; struggle and objection are pointless.

(chemistry) any isomer that differs from another isomer only in the position of a substituent, or of a double or triple bond

An archipelago and overseas territory of the United Kingdom in the southern Pacific Ocean.

It is allowable to retaliate against an enemy's dirty tricks by using the same ones against them. / Taking turns is morally right.

Abbreviation of Prince Edward Islander. / Inhabitant of Vancouver Island. / Clipping of Pacific Islander.

(in New York City) Long Island (in New York State) / (in British Columbia) Vancouver Island / (UK, colloquial) HM Prison Parkhurst, a prison on the Isle of Wight.

(anatomy) The lowest of the three bones that make up each side of the pelvis.

An Australian external territory and volcanic group of uninhabited Antarctic islands, between Madagascar and Antarctica.