Hi zoot999,
Welcome to Rootschat!

This may be William in 1881, newly married probably - then again in 1891 & 1901:
1881: At 1 Wellwynd, Airdrie, New Monkland, Lanarkshire
Ref: 651/1, ED11, PG19, HS86
Head: William WATT 23, Tube Worker, b England
Wife: Jane H WATT 19, b Co Down, Ireland
1891: At 11 Craig Street, Airdrie, New Monkland, Lanarkshire
Ref: 651/1, ED20, PG23, HS91
Head: William WATT 34, Tube Worker, b Edin., Edinburgshire
Wife: Jane WATT 27, b Ireland
Son: William WATT 9, b Airdrie
Son: George WATT 5, b Airdrie
Dau: Bella WATT 3, b Airdrie
Son: John WATT 1, b Airdrie
Lodger: John HARRISON 21, Coal Miner, b Ireland
The 1891 lodger is likely to be related to Jane, if not her brother - her maiden name appears to be HARRISON.
BIRTH:
https://familysearch.org/ark:/61903/1:1:XT6H-25SWilliam Harrison WATT
B 28 Oct 1881, Airdrie
Parents: William WATT & Jane HARRISON
1901: At 1/2 B Queen Victoria Str, Airdrie, New Monkland, Lanarkshire
Ref: 651, ED1, PG17, HS93
Head: William WATT 44, Tube Work Labourer, b Edinburgh
Wife: Jane WATT 39, b Ireland
Son: William WATT 20, Tube Work Labourer, b Airdrie
Son: George WATT 15, Messenger, b Airdrie
Dau: Bella WATT 13, b Airdrie
Son: James WATT 9, b Airdrie
Dau: Janet WATT 5, b Airdrie
Son: Thomas WATT 1 b Airdrie
Cheers
AMBLY