"Dahy" is not a word recognized in the English language. Perhaps you meant to write "Day," which refers to a period of 24 hours.
Synonyms for "day" include "24 hours," "sunlight," "daylight," "dawn," "morning," "afternoon," "evening," "midday," "noon," "daytime," "time," "cycle," "period," "turn," "interval," and "span."
Each of these synonyms offer a slightly different connotation or context for the word "day," but they are all useful to know when writing and speaking in English. By using different synonyms, we can add variety and depth to our language, making our communication more interesting and effective.