actinium Ac administrative and service staff PAS advanced mobile phone service AMPS aluminium Al aluminum Al American Anthropological Association AAA American Chemical Society ACS American Institute of Physics AIP American Mathematical Society AMS American Medical Association AMA American Political Science Association APSA American Psychological Association APA American Sociological Association ASA american standard code for information interchange ASCII americium Am Ancient Greek grc antimony Sb April Apr., Ap Arabic ar, ara argon Ar arsenic As astatine At asymmetric digital subscriber line ADSL August Aug., Ag barium Ba