Transpilation: text to text (eg: Scheme to C)
Compilation: anything to anything but usually it implies text to binary code
transpilation is compilation but compilation is not necessary transpilation (the all squares are rectangles but all rectangles ...)
But you can see the term of the day, "translator", here[0][1], and it isn't much of a leap to see how that evolved into translator-compiler, and then shortened itself.
[0] XLT86, 8080 to 8086 Translator http://www.s100computers.com/Software%20Folder/Assembler%20C...
[1] Pg. 47, Trans Z80 to 8086 Translator http://www.patersontech.com/dos/Docs/86_Dos_usr_03.pdf