Fieldday is likely misspelled.
Fieldday has no English definition.
As a noun payday is
the day of the week or month, or the specific day, on which an employee's wages or salary is paid.
fieldday
Not English
Fieldday has no English definition. It may be misspelled.
payday
English
Alternative forms
* pay day
Noun
(
en noun)
The day of the week or month, or the specific day, on which an employee's wages or salary is paid.
Derived terms
* payday loan