For example, in most dictionaries the word "land" shows the noun usage as the 1st entry, and the verb usage as the 2nd.
What do we call this kind of word?
I think you are referring to verbal nouns:
is a noun formed from or otherwise corresponding to a verb. Different languages have different types of verbal noun and different ways of forming and using them.
An example of a verbal noun in English is the word singing in the sentence "Singing is fun" (this is a noun formed from the verb sing). Verbal nouns may be non-finite verb forms such as infinitives or gerunds in English (or Latin) usage. They may also be "pure" verbal nouns, formed from verbs, but behaving grammatically entirely like nouns rather than verbs (not taking direct objects, for example). Such cases may also be called deverbal nouns.