Tabasco sauce is a brand of hot sauce made from tabasco chili peppers (Capsicum frutescens var. tabasco), vinegar, and salt, and aged in white oak barrels for three years. It has a hot, spicy flavour and is popular in many parts of the world.
Tabasco is trademarked as the brand name for the variety of tabasco sauce marketed by one of the United States' biggest producers of hot sauce, the McIlhenny Company of Avery Island, Louisiana.
Several new types of sauces are now produced under the name Tabasco Sauce, including jalapeño-based green, chipotle-based smoked, habanero, garlic, and "sweet and spicy" sauces. McIlhenny also produces a Tabasco soy sauce and Worcestershire sauce.
For a similar sauce to Tabasco, but more usable as a condiment, try my current favourite, Louisiana Hot Pepper Sauce.