Lambda Leonis (λ Leo, λ Leonis) is a star in the constellation Leo. It has the traditional name Alterf, from the Arabic الطرف aṭ-ṭarf "the view (of the lion)".
This star, along with ξ Cnc, were the Persian Nahn, "the Nose", and the Coptic Piautos, "the Eye", both lunar asterisms.
Lambda Leonis is of spectral class K5 and apparent magnitude +4.32. It is approximately 336 light years from Earth.
Coordinates:
- Right ascension: 09h 31min 43.240s
- Declination: +22° 58' 05.036"