The term 'legalese adverb' refers to a type of adverb used in legal documents. The eight solutions provided are all examples of legalese adverbs: 'thereto' (7 letters), 'thereat' (7 letters), 'hereto' (6 letters), 'hereof' (6 letters), 'hereunto' (8 letters), 'therein' (7 letters), 'herein' (6 letters), and 'thereof' (7 letters). Additionally, 'ian' (3 letters) is an abbreviation for the word 'herein'. Legalese adverbs are used to refer to other parts of a document, such as a clause or section, and are often used to indicate that something is being done in accordance with the document.