Generally speaking, inflection applies in more or less regular patterns to all members of a part of speech (for example, nearly every English verb adds "-s" for the third person singular present tense), while derivation follows less consistent patterns (for example, the nominalizing suffix "-ity" can be used with the adjectives "modern" and "dense", but not with "open" or "strong"). However, it is important to note that derivations and inflections can share homonyms, that being, morphemes that have the same sound, but not the same meaning. For example, when the affix -er, is added to an adjective, as in "small-er", it acts as an inflection, but when added to a verb, as in "cook-er", it acts as a derivation.