helper

Short definition from Wiktionary

Noun

1. 1
   One who helps; an aide; assistant; auxiliary.
2. 2
   That which helps; anything serving to assist.
3. 3
   A person who does cleaning and cooking in a family home, or in a market; domestic employee.
4. 4
   A locomotive that assists a train, usually on steep gradients.
5. 5
   A stimulating pill, especially amphetamine.

Proper noun

1. 1
   A city in Carbon County, Utah, United States, which got its name from the practice of the Denver & Rio Grande Railroad of attaching helper engines to trains there.
2. 2
   A surname; variant of Halpern or Helfer.