“Adposition” is the cover term for prepositions and postpositions.
Briefly, we consider an affix, word, or multiword expression to be adpositional if it:

1. mediates a semantically asymmetric figure--ground relation between two concepts, and

2. is a grammatical item that can mark an NP.
We annotate <i>tokens</i> of these items even where they mark clauses (as a subordinator) or are intransitive.[^1]
We also include always-intransitive grammatical items whose core meaning is spatial and highly schematic, like [p en/together], [p en/apart], and [p en/away].

Inspired by ([Huddleston and Pullum, 2002](/bib/huddleston_and_pullum_2002/)), the above criteria are broad enough to include a use of a word like [p en/before] whether it takes an NP complement, takes a clausal complement (traditionally considered a subordinating conjunction), or is intransitive (traditionally considered an adverb):

- [ex 001 "It rained [p en/before] the party. [NP complement]"]

- [ex 002 "It rained [p en/before] the party started. [clausal complement]"]

- [ex 003 "It rained [p en/before]. [intransitive]"]

Even though they are not technically adpositions, we also apply adposition supersenses to possessive case marking (the clitic [p en/'s] and possessive pronouns), and some uses of the infinitive marker [p en/to], as detailed in [Infinitive Clauses](/en/infinitive_clauses) and [Genitives/Possessives](/en/genitivespossessives/).

[^1]: Usually a coordinating conjunction, [p en/but]   only receives a supersense when it is prepositional, as described  under [ss PartPortion].