1d, In geometry, a solid shape with five faces such as a triangular prism or a square pyramid. P-D-A-E-R-N. 11 letters, saams to end in .....hedron but unable to complete! Thanks
Apologies, 35A, Piece of light or entertaining music in a number of movements without a fixed form, typically part of a chamber music suite. -i-e-t-m-n-o Thanks.