| overriding term(expression, reason, importance, significance) |
| pacing factor(expression, reason, importance, significance) |
| pacing item(expression, reason, importance, significance) |
| primal cause(expression, reason, importance, significance) |
| primary cause(expression, reason, importance, significance) |
| primary reason(expression, reason, importance, significance) |
| prime cause(expression, reason, importance, significance) |
| prime mover(expression, reason, importance, significance) |
| principal cause(expression, reason, importance, significance) |
| radical turn(expression, reason, importance, significance) |
| reason fundamental(expression, reason, importance, significance) |
| root cause(expression, reason, importance, significance) |
| root motive(expression, reason, importance, significance) |
| root source(expression, reason, importance, significance) |
| shaping factor(expression, reason, importance, significance) |
| top priority(expression, reason, importance, significance) |
| turning point(expression, reason, importance, significance) |
| ultimate cause(expression, reason, importance, significance) |
| underlying cause(expression, reason, importance, significance) |
| upstream cause(expression, reason, importance, significance) |