Dog and cat seizing old clothing item (8)

'clothing item' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?

'dog and cat seizing old' is the wordplay.
'dog' becomes 'tail' (synonyms).
'and' means one lot of letters go next to another.
'seizing' indicates putting letters inside (inserted letters are seized).
'old' becomes 'o' (abbreviation).
'cat' placed around 'o' is 'coat'.
'tail'+'coat'='TAILCOAT'

Can you help me to learn more?