/yü-nikz-i-zəm/
n. A piece of code or a coding technique that depends on the protected multi-tasking environment with relatively low process-spawn overhead that exists on virtual-memory UNIX systems. Common unixisms include: gratuitous use of 'fork(2)'; the assumption that certain undocumented but well-known features of UNIX libraries such as 'stdio(3)' are supported elsewhere; reliance on obscure side-effects of system calls (use of 'sleep(2)' with a 0 argument to clue the scheduler that you're willing to give up your time-slice, for example); the assumption that freshly allocated memory is zeroed; and the assumption that fragmentation problems won't arise from never 'free()'ing memory.
Compare vaxocentrism; see also New Jersey.