x1 is a thousand [1000; 103] of x2 in dimension/aspect x3 (default is units).
See also grake, mitre, snidu, stero, delno, molro, kelvo, xampo, gradu, litce, merli, centi, decti, dekto, femti, gigdo, gocti, gotro, megdo, mikri, milti, nanvi, petso, picti, terto, xatsi, xecto, xexso, zepti, zetro, minli