Lenticular are cumulus clouds-they belong to the cumulus family
Lenticularis (len) – clouds having the shape of a lens or almond, often very elongated and usually with well-defined outlines; they occasionally show irisation (iridescence). Such clouds appear most often in cloud formations of orographic origin, but may also occur in regions without marked orography. This term applies mainly to stratocumulus, altocumulus and cirrocumulus clouds.
From the met office-cloud facts site-or just basic PPL knowledge