It's a keyboard without a "ten-key." The term originated with mechanical adding machines from the early 1900s (prior to the Standard, most adding machines were multiple rows with 9 or 5 digits per row), so I'm fairly sure it's pretty safe to call any keyboard without a numberpad "tenkeyless." Besides, "numberpadless" is too awkward =X And looks a little too much like numberpaddles D:
And we all know what happens when numberpaddles get brought in to anything D: