as a synonym for `register' is a fairly reliable indication that
the user has been around for quite a while and/or that the
architecture under discussion is quite old. The term in full is
almost never used of microprocessor registers, for example, though
symbolic names for arithmetic registers beginning in `A' derive
from historical use of the term `accumulator' (and not, actually,
from `arithmetic'). Confusingly, though, an `A' register name
prefix may also stand for `address', as for example on the
Motorola 680x0 family. 2. A register being used for arithmetic or
logic (as opposed to addressing or a loop index), especially one
being used to accumulate a sum or count of many items. This use is
in context of a particular routine or stretch of code. "The
FOOBAZ routine uses A3 as an accumulator." 3. One's in-basket
(esp. among old-timers who might use sense 1). "You want this
reviewed? Sure, just put it in the accumulator." (See {stack}.)

:ACK: /ak/ interj. 1. [from the ASCII mnemonic for 0000110]
Acknowledge. Used to register one's presence (compare mainstream
*Yo!*). An appropriate response to {ping} or {ENQ}.
2. [from the comic strip "Bloom County"] An exclamation of
surprised disgust, esp. in "Ack pffft!" Semi-humorous.
Generally this sense is not spelled in caps (ACK) and is
distinguished by a following exclamation point. 3. Used to
politely interrupt someone to tell them you understand their point
(see {NAK}). Thus, for example, you might cut off an overly
long explanation with "Ack. Ack. Ack. I get it now".

There is also a usage "ACK?" (from sense 1) meaning "Are you
there?", often used in email when earlier mail has produced no
reply, or during a lull in {talk mode} to see if the person has