FORTH A programming language formerly much in vogue among users of microcomputers. FORTH operands are held on a stack, and programs take the form of strings in reverse Polish notation. A vital feature of FORTH is that a symbol (a WORD) can be associated with any program string, and such a user-defined word can then be used in expressions on equal terms with the system words (operators). This makes FORTH a flexible extensible language in which it is possible to define a customized language for, say, the control of a scientific instrument. The FORTH system is very compact; the interpreter and the dictionary containing the system-defined words can be fitted into 8K bytes. FORTH is now little used, but the same principles are found in PostScript.

forth / fôr[unvoicedth]/ • adv. chiefly archaic out from a starting point and forward or into view: the plants will bush out, putting forth fresh shoots. ∎  onward in time: from that day forth he gave me endless friendship.PHRASES: and so forth and so on: particular services like education, housing, and so forth.

forth forwards (now only in back and forth); onwards (surviving in gen. use in and so forth); forward into view; away. OE. forð = OS. forth (Du. voort), MHG. vort (G. fort) :- Gmc. *furþa (cf. Goth. faurþis further) :- IE. *pṛto-, f. base repr. in FORE-. forthcoming about or ready to appear XVI; ready to make advances XIX. forthright OE. forðriht adj., -rihte adv. forthwith †at the same time; immediately XIV; partly short for earlier forthwithal (XI), partly repl. ME. forth mid along with, at the same time as, used absol.