Tabasco is a very hot red sauce made from small chilli peppers, vinegar and salt, sold in a small bottle with a narrow neck. That narrow neck matters: the sauce is thin and fierce, so you shake it out drop by drop rather than pouring it. People put a few drops on eggs, pizza, soup, oysters, meat, or into drinks — a Bloody Mary is the classic one. Strictly speaking it is a brand name, made by one American family company in Louisiana since the 1860s, which is why you usually see it written with a capital T. In real life people use it much more loosely, as a general name for thin, vinegary chilli sauce of that type, in the same way people say 'Kleenex' for tissues. Careful writers and food companies keep the capital and treat it as the brand. Grammatically it is uncountable — 'some Tabasco', 'a few drops of Tabasco', not 'a Tabasco' — though you can order 'a bottle of Tabasco'. The name is also useful in a second, figurative way: to say something has Tabasco in it means it has a sharp, exciting kick, though this is casual and not common in writing.