1" is one inch 1' is one foot So yeah, a weird measurement unit. Technically the symbol to be used is a prime symbol (https://en.m.wikipedia.org/wiki/Prime_(s

1" is one inch 1' is one foot So yeah, a weird measurement unit. Technically the symbol to be used is a prime symbol (https://en.m.wikipedia.org/wiki/Prime_(symbol) https://en.m.wikipedia.org/wiki/Prime_(symbol)), but what’s used in practice is anything that looks close enough.