:leaf site: /n./ A machine that merely originates and reads Usenet news or mail, and does not relay any third-party traffic. Often uttered in a critical tone; when the ratio of leaf sites to backbone, rib, and other relay sites gets too high, the network tends to develop bottlenecks. Compare {backbone site}, {rib site}.
:leak: /n./ With qualifier, one of a class of resource-management bugs that occur when resources are not freed properly after operations on them are finished, so they effectively disappear (leak out). This leads to eventual exhaustion as new allocation requests come in. {memory leak} and {fd leak} have their own entries; one might also refer, to, say, a `window handle leak' in a window system.
:leaky heap: /n./ [Cambridge] An {arena} with a {memory leak}.
:leapfrog attack: /n./ Use of userid and password information obtained illicitly from one host (e.g., downloading a file of account IDs and passwords, tapping TELNET, etc.) to compromise another host. Also, the act of TELNETting through one or more hosts in order to confuse a trace (a standard cracker procedure).
:leech: /n./ Among BBS types, crackers and {warez d00dz}, one who consumes knowledge without generating new software, cracks, or techniques. BBS culture specifically defines a leech as someone who downloads files with few or no uploads in return, and who does not contribute to the message section. Cracker culture extends this definition to someone (a {lamer}, usually) who constantly presses informed sources for information and/or assistance, but has nothing to contribute.
:legal: /adj./ Loosely used to mean `in accordance with all the relevant rules', esp. in connection with some set of constraints defined by software. "The older =+ alternate for += is no longer legal syntax in ANSI C." "This parser processes each line of legal input the moment it sees the trailing linefeed." Hackers often model their work as a sort of game played with the environment in which the objective is to maneuver through the thicket of `natural laws' to achieve a desired objective. Their use of `legal' is flavored as much by this game-playing sense as by the more conventional one having to do with courts and lawyers. Compare {language lawyer}, {legalese}.
:legalese: /n./ Dense, pedantic verbiage in a language description, product specification, or interface standard; text that seems designed to obfuscate and requires a {language lawyer} to {parse} it. Though hackers are not afraid of high information density and complexity in language (indeed, they rather enjoy both), they share a deep and abiding loathing for legalese; they associate it with deception, {suit}s, and situations in which hackers generally get the short end of the stick.
:LER: /L-E-R/ /n./ [TMRC, from `Light-Emitting Diode'] A light-emitting resistor (that is, one in the process of burning up). Ohm's law was broken. See also {SED}.
:LERP: /lerp/ /vi.,n./ Quasi-acronym for Linear Interpolation, used as a verb or noun for the operation. "Bresenham's algorithm lerps incrementally between the two endpoints of the line."
:let the smoke out: /v./ To fry hardware (see {fried}). See {magic smoke} for a discussion of the underlying mythology.