firmboulder
nounUK /ˈfɜːmˌbəʊldə/
US /ˈfɜːrmˌboʊldər/
A firmboulder is a big, hard rock that does not move.
The children climbed onto the firmboulder by the river.
OTHER MEANINGS
2. A person who stays calm and steady when things are hard.
Grandpa is a firmboulder during storms.
3. A strong base that holds something up.
The bridge rests on a firmboulder of concrete.
4. A problem that is very hard to solve.
The math puzzle was a firmboulder for the whole class.