Where does “Lionel” come from?

Lionel is an English diminutive of Leo, from Latin leō, from Ancient Greek λέων meaning lion.

Ancestry of “Lionel”, step by step

Step	Language	Word	Meaning
1	French	Léon	—
2	Breton	Leon	—
3	Latin	leō	—
4	Ancient Greek	Λέων	—
5	Ancient Greek	λέων	lion; Leo, the zodiacal sign; lionheart, savage