27a genus of large flightless birds whose only extant member is the ostrich 8 letters -o-u- -i -
26a 5 letterts -r-s- in mathematics a three dimensional geometric figure whose cross section is constant in planes drawn perpendicular to its axis
16a 6 letters i- - -ng ancient chinese system of divination comprising a set of symbols 8 trigrams and 64 hexagrams and the text to interpret them 'book of changes'