A second screen buffer without scrollback, entered with ?1049, used by
full-screen programs so the shell's history survives.
APC
Application Program Command, ESC _ … ST. Carries the Kitty graphics
protocol; otherwise ignored. See Control strings.
Application
The program writing to the PTY: a shell, an editor, a TUI.
bce
Background color erase. Erased cells take the current background color.
C0, C1
The control-character sets at 0x00–0x1f and 0x80–0x9f. C1 has
seven-bit aliases ESC @–ESC _.
Cell
One column of one row in the grid. Wide characters occupy two.
ConPTY
The Windows pseudoconsole. Sits between every Windows terminal and its
applications and re-encodes the byte stream.
Control string
A sequence with an introducer (DCS, OSC, APC, PM, SOS), an opaque
payload, and a String Terminator. See
Control strings.
CPR
Cursor Position Report, CSI row ; col R.
CSI
Control Sequence Introducer, ESC [.
DA1, DA2, DA3
Device Attributes. Identity queries answered by every terminal.
DCS
Device Control String, ESC P … ST. Carries Sixel, DECRQSS, XTGETTCAP.
DEC private mode
A mode set with CSI ? Pm h. The namespace DEC reserved and xterm
extended.
DECRQM
Request Mode; the query that reports whether a mode is set or known.
DECSCUSR
Set Cursor Style.
Emulator
The program that owns the PTY master, parses the stream, and renders
cells.
Grapheme cluster
The user-perceived character defined by UAX #29; may be many code points.
Intermediate byte
A byte in 0x20–0x2f between parameters and the final byte of a CSI.
Kitty keyboard protocol
The progressive-enhancement keyboard encoding from kitty, adopted widely.
Mode
A persistent switch set with h, reset with l.
Multiplexer
tmux, screen, zellij. An emulator on one side, an application on the
other.
OSC
Operating System Command, ESC ] … ST. Titles, colors, hyperlinks,
clipboard.
Passthrough
Wrapping a sequence so a multiplexer forwards it to the outer terminal
unchanged.
Pending wrap
The state after printing in the last column: the cursor is drawn there and
the next character wraps first.
PM, SOS
Privacy Message (ESC ^ … ST) and Start of String (ESC X … ST), the
two ECMA-48 control strings no current emulator uses. A parser consumes
them silently. See Control strings.
PTY
Pseudo-terminal. The kernel object with a master (emulator) and slave
(application) end.
Report
Bytes the emulator writes to PTY input in reply to a query.
Scrolling region
The rows between the DECSTBM margins; the only rows that scroll.
SGR
Select Graphic Rendition, CSI Pm m.
Sixel
DEC's bitmap graphics format carried in a DCS.
ST
String Terminator, ESC \.
Sub-parameter
A :-separated part of one CSI parameter; used by SGR.
terminfo
The capability database keyed by TERM.
Truecolor
24-bit color selected with SGR 38;2;r;g;b.
wcwidth
The C function, and by extension the algorithm, that maps a code point to
a cell width of −1, 0, 1, or 2.
XTVERSION
xterm's CSI > 0 q query returning the emulator name and version.