Mould

mould ² |məʊld| (USmold)

noun [ mass noun ]

a furry growth of minute fungi occurring typically in moist warm conditions, especially on food or other organic matter. mould may flourish unhindered. [ count noun ] : moist food becomes covered with moulds.

●The fungi belong to the subdivision Deuteromycotina (or Ascomycotina).

When we build a building especially hospitals, we are always careful with those molds showing up on the wall. Even a tiny mold can cause the whole wall to be torn down. The reason is mold can be caused by a leak from hot/cold/heating hot water/sewage pipes inside the drywall. I have seen the whole brand new walls were taken out by appearance of a single teeny tiny mold on the wall. A while ago I went to one of the large hospital for working class people. A lot of hospital walls inside and out are covered with the molds. Unacceptable. Personal opinion only