adverbial complement
Definition - An adverbial that is a necessary sentence element (i.e. if you remove it, the sentence ceases to be well-formed).

1. As opposed to adverbial adjuncts, so called because they can be removed from well-formed sentences and the sentences remain well-formed.

Example -
Bob is in the garden
(If you remove the adverbial complement in the garden, the sentence ceases to be well-formed.)

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