Definition of Micro-

Micro-: Prefix derived from the Greek "mikros" meaning small. Examples of the many biomedical terms containing "micro-" include the following:

microangiopathy,
microcephaly,
microcystic (as in microcystic corneal dystrophy),
microhematuria,
microorchidism,
micropenis,
microphallus,
micropigmentation ,
microscope,
microscopy (as in electron microscopy), and
microsomia.

In premed and medical student lingo, micro is short for microbiology (or microscopic anatomy, i.e. histology).

The opposite of micro- is macro-.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=4371
Last Editorial Review: 10/17/2004