alicyclic compound(Any substance composed of two or more unlike atoms held together by chemical bonds characterized by straight-chained, branched or cyclic properties)
alicyclic hydrocarbon(A class of organic compounds containing only carbon and hydrogen atoms joined to form one or more rings and having the properties of both aliphatic and cyclic substances)
alignment(The selection and detailed layout of public transport routes in the light of construction, operation, service, technology, and economic criteria)