amanuensis
noun /əˌmænjuˈensɪs/
  /əˌmænjuˈensɪs/
(plural amanuenses 
 (formal) /əˌmænjuˈensiːz/
  /əˌmænjuˈensiːz/
)- a person who writes down your words when you cannot write, for example if you are injured and have an exam
 - an assistant, especially one who writes or types for somebody
 
Word Originearly 17th cent.: Latin, from (servus) a manu ‘(slave) at hand(writing), secretary’ + -ensis ‘belonging to’.