Glissando is the act of sliding from one pitch to the next with the same finger.
Glissando can take place over the entire range of the instrument and is available in conjunction with all techniques that do not mute the strings. It can take place from the start of a note or at any point through an already sounding pitch.
The final (terminal) pitch can be specified or unspecified.
Brian Ferneyhough Trittico Per G.S (1989)
Barry Guy Statements II (1972)
Iannis Xenakis Theraps (1976)