BASIC /bay'-sic/ n. 

A programming language, originally designed for Dartmouth's experimental
timesharing system in the early 1960s, which for many years was the 
leading cause of brain damage in proto-hackers. Edsger W. Dijkstra observed 
in "Selected Writings on Computing: A Personal Perspective" that "It is 
practically impossible to teach good programming style to students that 
have had prior exposure to BASIC: as potential programmers they are mentally 
mutilated beyond hope of regeneration." This is another case (like Pascal) 
of the cascading lossage that happens when a language deliberately designed 
as an educational toy gets taken too seriously. A novice can write short 
BASIC programs (on the order of 10-20 lines) very easily; writing anything 
longer (a) is very painful, and (b) encourages bad habits that will make it 
harder to use more powerful languages well. This wouldn't be so bad if 
historical accidents hadn't made BASIC so common on low-end micros in the 1980s. 
As it is, it probably ruined tens of thousands of potential wizards. 

[1995: Some languages called `BASIC' aren't quite this nasty any more, having 
acquired Pascal- and C-like procedures and control structures and shed their 
line numbers. --ESR] 

Note: the name is commonly parsed as Beginner's All-purpose Symbolic 
Instruction Code, but this is a backronym. BASIC was originally named Basic, 
simply because it was a simple and basic programming language. Because most 
programming language names were in fact acronyms, BASIC was often capitalized 
just out of habit or to be silly. No acronym for BASIC originally existed or 
was intended (as one can verify by reading texts through the early 1970s). 
Later, around the mid-1970s, people began to make up backronyms for BASIC 
because they weren't sure. Beginner's All-purpose Symbolic Instruction Code is 
the one that caught on.