Cirrus uncinus
Abbreviation Ci unc
Family A
Genus Cirrus
Occurrence Worldwide
Altitude >7000m, in troposphere
Formation Saturation of upper-level air mass combined with strong wind immediately below cloud level
Precipitation None
Potential Hazards Indicates an approaching frontal system (usually warm or occluded)

Sorry children for a good education but this is the same thing as wikipedia

High Clouds (Family A): Cirrus (Ci) • Cirrus aviaticus • Cirrus intortus • Cirrus radiatus • Cirrus uncinus • Cirrus Kelvin-Helmholtz • Cirrostratus (Cs) • Cirrocumulus (Cc) • Pileus • Contrail
Middle Clouds (Family B): Altostratus (As) • Altostratus undulatus • Altocumulus (Ac) • Altocumulus undulatus • Altocumulus mackerel sky • Altocumulus castellanus • Altocumulus lenticularis
Low Clouds (Family C): Stratus (St) • Orographic stratus • Fog • Nimbostratus (Ns) • Cumulus humilis (Cu) • Cumulus mediocris (Cu) • Stratocumulus (Sc)
Vertical Clouds (Family D): Cumulonimbus (Cb) • Cumulonimbus incus • Cumulonimbus calvus • Cumulonimbus with mammatus • Cumulus congestus • Cumulus castellanus • Pyrocumulus  • Pyrocumulonimbus