The Collaborative International Dictionary of English v.0.48:

ftp \ftp\, FTP \FTP\([e^]f`t[=e]*p[=e]"), n. [acronym from File
   Transfer Protocol.] (Computers)
   An acronym for file transfer protocol, a standardized
   protocol used to allow transmission of files between
   computers; as, send me the file by ftp. It consists of a set
   of coded signals which are transmitted between computers, and
   which inform the receiving computer of the nature of a packet
   of information to be transmitted, and inform the transmitting
   computer when a packet has been successfully received.
   [acronym]
   [PJC] ftp

WordNet (r) 3.0 (2006):

file transfer protocol
    n 1: protocol that allows users to copy files between their
         local system and any system they can reach on the network
         [syn: file transfer protocol, FTP]

The Free On-line Dictionary of Computing (30 December 2018):

File Transfer Protocol
FTP

   (FTP) A client-server protocol which allows a user on one
   computer to transfer files to and from another computer over a
   TCP/IP network.  Also the client program the user executes
   to transfer files.  It is defined in STD 9, RFC 959.

   See also anonymous FTP, FSP, TFTP.

   Unix manual page: ftp(1).

   (1994-12-01)