1. So thin as to transmit light
   - diaphanous, filmy, gauzy, gossamer, see-through, sheer, transparent, vaporous, vapourous [Brit, non-standard], cobwebby, vapory [US], vapoury [Brit, Cdn]

See also: thin

• uniovulate
• uniparous
• unipod
• unipolar
• unipolar depression
• unique
• uniquely
• uniqueness
• uniquity
• unironed
• unisex
• unisexual
• unison
• unit
• unit cell
• unit character
• unit cost
• unit investment trust
• unit matrix
• unit of ammunition
• unit of measurement
• unit of time
• unit of viscosity
• unit trust
• unitard