Refers to the magnitude of an offering, an order, or a trade. Large as in the size of an offering, the size of an order, or the size of a trade. Size is relative from market to market and security to security. "I can buy size at 102-22," means that a trader can buy a significant amount at 102-22. Small is <10,000 shares. Medium is 15,000-25,000 shares. Good is 50,000 shares. Size is 100,000 shares. Good six-figure size is 200,000-300,000 shares. Multiple six-figure size is >300,000 shares. Size of the market is actual number of shares represented in one's market, or bid and offering; unless specified, assumed to be at least 500 to 1000 shares, depending on the stock.