| hypothesis /haɪˈpɒθəsɪs/ | an idea that is tested in an experiment | Our hypothesis was that salt water freezes more slowly. |
| empirical /ɪmˈpɪrɪkl/ | based on observation and experiments, not theory | There is no empirical evidence that the diet works. |
| significant /sɪɡˈnɪfɪkənt/ | large or important enough to notice | There was a significant improvement in her results after the course. |
| valid /ˈvælɪd/ | based on good reasons; logically sound | That's a valid point — I hadn't thought of it. |
| criterion /kraɪˈtɪəriən/ | a standard used to judge something (plural: criteria) | Price was the main criterion when we chose the hotel. |
| comprehensive /ˌkɒmprɪˈhensɪv/ | including everything that is needed | The guidebook gives a comprehensive list of museums in the city. |
| subsequent /ˈsʌbsɪkwənt/ | happening after something else | The first film was a hit, but subsequent sequels were disappointing. |
| aforementioned /əˌfɔːˈmenʃənd/ | mentioned earlier in the same text | The aforementioned museum is open every day except Monday. |
| whereby /weəˈbaɪ/ | by which; through which (formal) | The school has a system whereby older students help younger ones. |
| crucial /ˈkruːʃl/ | extremely important | Sleep is crucial for memory and concentration. |