what is MOULD?

i was researching some sites and i finally realised that some sites used 'mold' and some used 'mould'. i got confused because on my laptop i typed "mold' it had the red squiggly lines underneath but on the site, when i types 'mould' there would be red lines underneath. i googles this and i have concluded that MOULD is the correct one to use in Australia.

Anyways, back on topic, what is MOULD?

according to this site: http://www.buzzle.com/articles/bread-mold-growth.html
it is "Mold growing on the bread can be microscopic fungi belonging to different species like Penicillium, Rhizopus, Aspergillus, Monascus and Fusarum. They are of different shapes and colors depending on the species. Rhizopus stolonifer is the most common and fast growing bread mold. It is also known as black mold as it appears dark green or black in color. It causes rotting of some fruits and some infections in humans."

that didn't really explain much to me so i searched around for more meanings...

this site: http://www.wisegeek.com/what-is-mold.htm states,
"Mold is a type of fungus that grows on plants and fibers and is most often associated with damp, musty locations such as bathrooms, basements and attics. Mold travels through the air as tiny spores which like to make their home in wet areas, where they will breed."

and this site: http://www.cccf-fcsge.ca/healthy-spaces/mould_en.php
"Mould is part of the fungus family, along with mushrooms and yeast. Mould spores are very small and they travel easily through the air."

and good ol' wiki (http://en.wikipedia.org/wiki/Mold) says

"Mold are fungi that grow in the form of multicellular filaments, called hyphae.^[1] In contrast, microscopic fungi that grow as single cells are called yeasts. A connected network of these tubular branching hyphae has multiple, genetically identical nuclei and is considered a single organism, referred to as a colony or in more technical terms a mycelium.

Molds do not form a specific taxonomic or phylogenetic grouping, but can be found in the divisions Zygomycota, Deuteromycota and Ascomycota. Some molds cause disease or food spoilage, others play an important role in biodegradation or in the production of various foods, beverages, antibiotics and enzymes."