Luth

6 clues
A Prot.
Certain Prot.
Leatherback turtle
Protestant group: Abbr.
Particular Protestant: Abbr.
Protestant in Garrison Keillor stories: abbr.
Similar answers:
Aaaautoclub
Aalu
Aaronbirth
Aattheopera
Aattheraces
Abaculus
Abadwaytolunch
Abath
Abathingbeauty
Abdominalthrust
Abenchinthepark
Abernathy
Abguthrie
Abidebytherules
Abidingfaith
Abirdinthehand
Abirdinthesand
Abitontheside
Ablue
Abluent