AT&T 6300 Programmer's Manual page 696

Glossary
overflow In an arithmetic operation, the generation of a
quantity beyond the capacity of a register or
location which is to receive the result.
overlay Programs too large for memory can be divided
into logical segments (or overlays).
parameter Value supplied to a command or language
statement that provides additional information
for the command or statement. Used
interchangeably with argument. An "actual
parameter" is a value that is substituted for a
"formal parameter" in a given procedure or
function when invoked.
pixel A graphics "point" addressable on the screen
by its coordinates (x,y). Also, the bits which
contain the information for that point.
port An access channel for data entry or exit.
program mode This mode is used to enter into memory a
GWBASIC program line. To tell GWBASIC the
line you are entering is part of a program, you
begin the line with a line number. A program
line is stored in memory when you press CR,
but it is not executed. The lines are stored in
memory in line number sequence to form a
GWBASIC program. To execute the program
press RUN CR
14