• A Ampere
• A/UX Apple UniX
• AA Auto Answer / Add Accelerator
• AACE Association for the Advancement of Computing in Education
• AARP AppleTalk Address Resolution Protocol
• ABIOS Advanced BIOS
• ABP Alternate BiPolar
• AC Alternating Current
• ACDI Asynchronous Communication Device Interface
• ACID Atomic, Consistent, Isolated, Durable
• ACK ACKnowledgement
• ACL Access Control List
• ACM Association of Computing Machinery / Audio Compression Manager
• ACS Asynchronous Communication Server
• ACTLU ACTivate Logical Unit
• ACTPU ACTivate Physical Unit
• ACTT Advanced Communications and Timekeeping Technology
• ACU Access Control Units
• AD Administrative Domain
• ADF Automatically Deferred Function
• ADPCM Adaptive Differential Pulse-Code Modulation
• ADSP AppleTalk Data Stream Protocol
• ADSS Apple Data Stream Protocol
• AEP AppleTalk Echo Protocol
• AFI Authority and Format Indicator
• AFM Added Font Metrics
• AFP Apple Filing Protocol
• AFRP Arcnet Fragmentation Protocol
• AFS Andrew File System
• AGS Asynchronous Gateway Server
• AGU Address Generation Units
• AI Artificial Intelligence
• AIR Apple Internet Router
• AIX Advanced Interactive EXecutive
• ALGOL ALGOrithmic Language
• ALMS Appware Loadable ModuleS
• ALU Arithmetic Logic Unit
• AM Active Monitor
• AMD Advanced Micro Devices
• AMI Alternate Mark Inversion
• AMP Apple Management Protocol
• AMT Address Mapping Table
• ANS Advanced Network System
• ANSI American National Standards Institute
• AO/S Agents Object System
• AOCE Apple Open Collaboration Environment
• AOL America OnLine
• APA All Points Addressable
• API Application Programming Interface
• APL A Programming Language
• APM Advanced Power Management
• APPC Advanced Program-to-Program Communications
• APPN Advanced Peer-to-Peer Networking
• ARA Apple Remote Access
• ARAP AppleTalk Remote Access Protocol
• ARCNET Attached Resource Computer NETwork
• ARE All Routes Explorer
• ARI Address Recognized Indicator Bit
• ARIES ATM Research & Industrial Enterprise Study
• ARP Address Resolution Protocol
• ARPA Advanced Research Projects Agency
• ARPANET Advanced Research Projects Agency NETwork
• AS Autonomous System
• ASAD Association of Software Authors and Distributors
• ASC Advanced Software Concepts
• ASCII American Standard Code for Information Interchange
• ASI Adapter Support Interface
• ASIC Application-Specific Integrated Circuit
• ASN.1 Abstract Syntax Notation 1
• ASP Association of Shareware Professionals / Association of Shareware Programmers / AppleTalk Session Protocol
• ASPI Advanced SCSI Programming Interface
• AST Automatic Scheduled Testing
• ASTRAL Alliance for Strategic Token Ring Advancement and Leadership
• AT Advanced Technology
• AT&T American Telephone & Telegraph
• ATDT ATtention Dial Tone
• ATM Asynchronous Transfer Mode / Adobe Type Manager
• ATOB ASCII TO Binary
• ATP AppleTalk Transaction Protocol
• ATT Automatic Toll Ticketing
• AUI Attachment Unit Interface
• AUP Acceptable Use Policy
• AURP Apple Update Routing Protocol
• AVI Audio Video Interleave
• AWG American Wire Gauge
• AWK Ano, Weinberger and Kernighan