μηκύνηται [1 verse]( verb 3rd sg fut ind mid or verb 3rd sg pres subj mp or verb 3rd sg aor subj mid ) "Grow up" is from mekuno, which means "to lengthen," "to make long," "to prolong," "to grow tedious," "stretch out a syllable," and "to multiply by some factor."  - "Grow up" is from a unique verb for Jesus to us. It means "to lengthen," "to make long," "to prolong," "to grow tedious," "stretch out a syllable," and "to multiply by some factor." The meaning of "to lengthen," if a bit of word play, where Jesus describes what he is doing in the story by using a long of "ands." It also means "to multiply by some factor," which is the likely meaning here given the context. The tense of this verb, which seems odd because the man is described in the present. However, in the alternative, you can see how it words that way, giving a sense that time passed in the "day" and "night" section.