byways
Bellybuttons would be the longest word I can think of beginning with a 'b' and ending in an 's'.
Eight letter words beginning with b, ending with e:backsidebaselinebegrudgebelittleblockadeblockagebreakage
thumb
cherrub
thumb
Ballerina is one 9-letter word beginning with B and ending with A.
Some seven letter words starting with B are:bathtubdisturbperturbproverbrhubarbsuccumbtaxicabwashtub
Caleb fdhrsb
carob climb
baobab.
bath