Definition of mosquito for English Language Learners. : a small flying insect that bites the skin of people and animals and sucks their blood.
What it is: Small-cap stock refers to a company with a market capitalization (calculated by taking a firm's current share price and multiplying that figure by the total number of shares outstanding) near the low end of the publicly traded spectrum.
Large cap stocks are stocks of companies which have large market capitalizations, typically over $10 billion. They tend to be very established in their line(s) of business and highly diversified in their operations.