a three-legged stool
She fell off her stool.
The first stool examination was performed on 210 children in each neighourhood.
Aside from worm numbers, egg output also depends on processes such as faecal output and stool consistency, which are likely to differ systematically between individuals.
The average annual isolation rate was 76.2 per 100 000 persons for blood+stool isolates, and 2.0 per 100 000 for blood isolates alone.
