title_body: Syntactic word that carries no meaning - is there a name for that? Is there a name for words that exist purely for syntactic reasons and carry no lexical meaning?
  
  Reason:
  Some forms of sentence in my language don't have verbs, but information such as tense and mood are indicated by affixes on the verb. So, in cases where you need to modify the verb, a meaningless verb fills in; the verb carries no meaning on its own, existing just to hold affixes.
  
  Example:
  Here is a sentence without a verb. No verb is used for just applying an adjective to a noun. Adjectives are applies directly to the noun.
  Mopifa-di-mopi
  Life-(adj-on)-wood
  The wood is alive.
  
  But (for example), past tense is marked by a suffix on the verb so it needs a verb to attach onto; ta "stands in" for the absent verb, giving -to (past tense) something to attach to.
  Ta-to mopifa-di-mopi
  (null)-(past) life-(adj-on)-wood
  The wood was alive.
  
  "Ta" is the word I'm talking about.
upvoted_answer: One general term would be function words; these are words that do not carry any lexical meaning, but are used to link content words together and clarify their relationships (eg in the case of prepositions or conjunctions).
  
  It is indeed difficult to see exactly what you have in mind without any examples; other possibilities would be particle, which is eg used in Japanese to mark certain grammatical features (such as 'direct object'). 
  
  Some people use the term empty verb for the auxiliary in phrases like to have/take a shower, where you could just use to shower directly; here you can add the tense feature to the auxiliary as in She had/took a shower.
  
  As an aside: there are no words that "carry no meaning". If a word has no meaning, it is redundant, and would not be there at all. In linguistics you distinguish between lexical meaning and functional/grammatical meaning: the former you would find in a dictionary definition, whereas the latter is not always easy to put into words, as it describes relationships between elements in and structure of a sentence.
  
  Update after example: Hard to say. A particle usually doesn't change its form (at least in English and most other natural languages I know), so the fact that the marker -to is attached to it would rule that possibility out in my view. That would leave empty verb as the most likely option, but then it is not really necessary when the marker is not used. I guess it would still be my preference, though.