Mildew is a common term used for certain fungal growth or a mold-like surface appearance. It does not provide a precise identification of an organism.
What this means at your property
A recurring patch near a window may be associated with moisture, but its color or common name does not establish the cause. Cleaning the visible patch without investigating recurring dampness can leave the underlying condition unchanged.
Is a mildew smell enough to select a treatment?
No. Record when the smell occurs, any leak history and the surfaces involved. Ask for an assessment of the source and materials before choosing products or assuming that a fragrance resolves the concern.
Related terms
Further reading: EPA: mold and related terminology.