Earlier quoted context omitted.
As in a manhole cover in a street for maintenance.
Yes, yes. Seems like an outdated term. Downvotes accepted.
Manhole is, indeed, an outdated term. Generally the preferred term is "Maintenance Hole". Still abbreviated MH, and people in the field use all three interchangeably (much like metric/imperial).
Source: I work with storm/sanitary/electrical maintenance holes.