| element(law, foundation, basic, stipulation, tenet) |
| essentiality(cause, source, origin) |
| factor(law, foundation, basic, stipulation, tenet) |
| foot |
| fountain(cause, source, origin) |
| fountainhead(cause, quick, source, origin, stem) |
| germ(cause, source, origin) |
| ground rule(expression, stipulation, tenet, axiom) |
| guts(law, foundation, basic, stipulation, tenet) |
| inception(cause, source, origin) |
| infrastructure(cause, quick, source, origin, stem) |
| law(foundation, basic, stipulation, tenet, axiom) |
| low point |
| mainspring(cause, quick, source, origin, stem) |
| marrow(cause, source, origin) |
| modus operandi(expression, stipulation, tenet, axiom) |
| motive(cause, source, origin) |
| nitty-gritty(law, foundation, basic, stipulation, tenet) |
| nub(cause, source, origin) |
| nucleus(cause, source, origin) |