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/nɪkˈθɛm.(ə.)ɹəl/ · adjective
Relating to or lasting a nychthemeron (a period of 24 hours)..
Observations on sea-anemones in dimly lighted situations, such as under bridges and so forth, showed that these animals were more or less continuously expanded, but aside from such exceptions it was clear that Metridium in its natural surroundings exhibited a well-marked nychthemeral rhythm.
Use nychthemeral when its meaning, tone and grammar fit the full sentence. A synonym is not always a direct replacement.
Nychthemeral means Relating to or lasting a nychthemeron (a period of 24 hours)..
The closest synonym depends on the sentence and intended sense.
The opposite depends on the specific sense.
Observations on sea-anemones in dimly lighted situations, such as under bridges and so forth, showed that these animals were more or less continuously expanded, but aside from such exceptions it was clear that Metridium in its natural surroundings exhibited a well-marked nychthemeral rhythm.
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