shveta = white (cf. Russian 'svetlyi') ashvatara = mule; literally (comparative of a *substantive*!) 'better (-tara) horse (ashva)'
shvetaashvatara, a bahuvriihi compound: (having) white mule(s). QED! zvetAzvatara m. `" having white mules "'N. of a teacher S3vetUp. ; pl.his school TA1r. Sch. ;