What is the definition of a base in chemistry? Bases Bases are substances that are soapy to touch and bitter in taste. Substances containing a base are called basic substances. Sodium hydroxide (NaOH) and calcium hydroxide [Ca(OH)2] are examples of bases used in the laboratory. Corn starch, fresh egg white, etc., are other examples of bases. Bases may have a strong … [Read more...] about What is the definition of a base in chemistry