MAINFRAME: Uncertain origin, but the Computer History Museum believes the use of term "main frame," originating in pre-computer days in the mechanical and telecom industries, arose in the first half of the 1960s as a reference to a central processor of the computer, or more generally the computer without the peripherals. The compound word "mainframe" developed closer to the 1970s as smaller mini-computers were common to identify the larger, general purpose machines. According to the Museum, "IBM, the company most people today would associate with being a mainframe manufacturer, did not embrace the term as a name for a category of computers until probably the early 1980s. You certainly will not find the word 'mainframe' in the 1964 IBM System/360 Principles of Operation."

MALWARE: A term to describe the wide range of malicious code, it was first used by Yisrael Radai on July 4, 1990, in a public posting in which he wrote: "Trojans constitute only a very small percentage of malware (a word I just coined for trojans, viruses, worms, etc)." Chris Klaus gets credit for being the first to widely use the word malware in presentations.

ONE-TRANSITOR DYNAMIC RAM (DRAM) -- Almost all computer chips today use Dynamic Random Access memory (DRAM) technology in which each bit of information is stored in a memory cell consisting of one transistor and a tiny capacitor. IBM researcher Robert Dennard was awarded US patent #3,387,286 in 1968. Today's DRAM chips typically store 64 million bits, and DRAM is a key component of a wide variety of computers and electronics.

PUBLIC KEY, PRIVATE KEY: Whitfield Diffie says he coined the term "public key" in the spring of 1975 to describe the encryption method he was formulating during his time as an "itinerant cryptographer" getting by on a Stanford University research grant with support from an understanding wife with a corporate job.

Today, Diffie's visionary public-key encryption concept is widely regarded as a eureka moment in data security. Users no longer had to exchange a secret key -- which had to always be kept secret -- to encrypt and decrypt messages to each other. Instead, a public key for a message recipient could be published to the world that was tied to a secret key -- Diffie called it the "private-key" -- that the recipient would use to unlock the scrambled data. Diffie, who presented his public-private key exchange ideas at the National Computer Conference in 1976, teamed with Stanford University professor Marty Hellman to publish the paper "New Directions in Cryptography" the same year.

Diffie says the development and elaboration of the public-private key pair is as much Hellman's work as his own. Diffie isn't wholly satisfied he choose the word "private" to coin the term "private key" since "privacy has so many different meanings," he points out. But he adds the world would do well to consider his wife, Mary Fischer, to whom he's been married 35 years, "the Mother of Public-Key Cryptography" because she was both inspiration and support in the difficult early days of its invention.

PUNCH CARD: A paper card used for early computing instructions, the term appears to have officially originated with Herman Hollerith, the inventor of the electric tabulating system for the 1890 US Census.

REDUCED INSTRUCTION SET COMPUTING: Based on an invention by IBM scientist John Cocke in the early 1970's, RISC is the acronym widely used to describe a CPU design strategy based on the notion that simplified instructions that "do less" may still provide for higher performance, giving rise to the expression "RISC-based architectures" to describe how some computers work. (Bio of John Cocke.)