Leonard Hofstadter:  Cats , Sheldon . You 're clearly upset about Amy being gone , and you 're trying to replace her with a bunch of cats .
Sheldon Cooper: Clowder .
Leonard Hofstadter: What ?
Sheldon Cooper: A group of cats is a clowder . Or a glaring .
Leonard Hofstadter: Okay , yeah , fine .
Sheldon Cooper: It 's the kind of thing you ought to know now that we have _ one _ .