1. preposition - Noun
2. preposition - Verb
A word employed to connect a noun or a pronoun, in an adjectival or adverbial sense, with some other word; a particle used with a noun or pronoun (in English always in the objective case) to make a phrase limiting some other word; -- so called because usually placed before the word with which it is phrased; as, a bridge of iron; he comes from town; it is good for food; he escaped by running.
A proposition; an exposition; a discourse.
Source: Webster's dictionaryThe rule which forbids ending a sentence with a preposition is the kind of nonsense up with which I will not put. Winston Churchill
You can't fight a war on terror if you're ending a sentence with a preposition. John Hodgman
Alternatively, the accusative may be used without a preposition: :ili iros la trian de majo. Source: Internet
An unofficial but widely recognized accusative preposition na has become popular with some Esperantists on the internet and may be used in such situations, especially when there is no following noun (ties, accusative na ties). Source: Internet
Another wide group of adverbs are formed by gluing preposition to following oblique case form (now often dialectical or deprecated): з from+рідка the rare→зрідка rarely, на onto+долину bottom→надолину downwards. Source: Internet
Based on the meaning the preposition express, they can be divided into prepositions of time, place, manner and quantity. Source: Internet