pin·feath·er 
(pĭnfĕth′ər)
(pĭnfĕth′ər)n.
A growing feather still enclosed in its horny sheath, especially one just emerging through the skin.
- biological
- biological clock
- biological computing
- biological control
- biological drug
- biological half-life
- biologically
- biological oxygen demand
- biological response modifier
- biological warfare
- biological weapon
- biologist
- biology
- bioluminescence
- bioluminescent
- biolysis
- biolytic
- biomagnetism
- biomagnification
- biomarker
- biomass
- biomaterial
- biomathematical
- biomathematician
- biomathematics