Define ethers and nomenclature.

Here are the answers to your questions:

1. Ethers are a class of organic compounds characterized by an oxygen atom connected to two alkyl or aryl groups. Their general formula is R-O-R', where R and R' can be the same or different hydrocarbon groups. A common example is diethyl ether ($\text{CH}_3\text{CH}_2\text{OCH}_2\text{CH}_3$).

2. Nomenclature refers to a system of naming things, especially in a particular art or science. In chemistry, it's the systematic method used to name chemical compounds, ensuring that each compound has a unique and unambiguous name (e.g., IUPAC nomenclature).