| foundation(noun, regulation, rule, standard) |
| ground(noun, regulation, rule, standard) |
| origin(noun, regulation, rule, standard) |
| rock bottom(noun, expression, foundation, basic) |
| source(noun, regulation, rule, standard) |
| usage(noun, regulation, rule, standard) |
| ABCs(noun, foundation, basic, fundamental) |
| basic(noun, foundation, fundamental, shorts) |
| bottom line(noun, expression, foundation, basic) |
| brass tacks(noun, expression, foundation, basic) |
| coal and ice(noun, expression, idiom, foundation) |
| constituent(noun, foundation, basic, stipulation) |
| cornerstone(noun, foundation, basic, stipulation) |
| dogma(noun, rule, notion, fundamental) |
| essential part(noun, expression, foundation, basic) |
| ethic(noun, rule, notion, fundamental) |
| factor(noun, foundation, basic, stipulation) |
| guts(noun, foundation, basic, stipulation) |
| heart(noun, foundation, basic, fundamental) |
| nitty-gritty(noun, foundation, basic, stipulation) |