math.frexp - what's it mean?

[Skip Montanaro]

    >>> mantissa, exponent = math.frexp(5e40)

Not being a numeric type person, "frexp" conjured up absolutely no mnemonic
significance for me.  The library reference manual was no help either.
Finally, I tried "man frexp" and got "convert floating-point number to
fractional and integral components".  Now I know what it means mnemonically
("FRaction EXPonent", I guess), but the name is still perplexing.  Why not
"manexp"?  Does its use predate its appearance in C?

Skip