-al (1) Look up -al at Dictionary.com
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).
-al (2) Look up -al at Dictionary.com
suffix forming nouns of action from verbs, mostly from Latin and French, meaning "act of ______ing" (such as survival, referral), Middle English -aille, from French feminine singular -aille, from Latin -alia, neuter plural of adjective suffix -alis, also used in English as a noun suffix. Nativized in English and used with Germanic verbs (as in bestowal, betrothal).
-al (3) Look up -al at Dictionary.com
word-forming element in chemistry to indicate "presence of an aldehyde group" (from aldehyde). The suffix also is commonly used in forming the names of drugs, often narcotics (such as barbital), a tendency that apparently began in German and might have been suggested by chloral (n.).