Nature in the language of the play serves two functions. First, it relates love to nature, or what is natural. In this play, love is significantly guided by the seasons. The first place in which we see love being guided by the seasons is in the title of the play. Earlier historical periods, such as Shakespeare's era, only considered there to be three seasons, which were autumn, winter, and summer. Midsummer was considered to begin in May and the action of the play starts the night before May Day ("Historical Background," eNotes). May Day is typically a day in which fertility is celebrated. Hence, we see that even with the language of the title, Shakespeare has made a connection between nature and love, showing us that love is part of the natural course of life. A second place in which we see love being governed by nature in the play is when Theseus opens the play by mentioning that he and Hippolyta are waiting for the full moon to change to the new moon, which is the day they will marry. The new moon represents birth or a fresh start making it the perfect symbolic time to begin a marriage. We see Theseus pining for the moon to change and, thus, pining for the opportunity to consummate his marriage in the lines, "Another moon; but, O, methinks, how slow / This old moon wanes! She lingers my desires" (I.i.3-4).
The second way in which nature is used in the language of the play is that it serves to link the human world to the fairy world, thereby linking love to a dreamlike state. The fairies live their lives surrounded by nature. In fact, they even manipulate nature. We see the fairies manipulate nature through both Oberon's and Puck's use of the flower that has been shot with Cupid's arrow to manipulate individual's into falling in love. The use of the flower manipulates Demetrius into rightfully falling in love with Helena and Lysander into rightfully remaining in love with Hermia; however, it also produces for the lovers a dreamlike state. After waking and explaining what they could to Theseus, the two couples continue to question whether or not they are dreaming, as we see in Demetrius's lines:
Are you sure
That we are awake? It seems to me
That yet we sleep, we dream. (IV.i.195-197)
Hence, we see that through manipulating nature, the fairies created an ideal state of love that was so perfect it was like a dream, thereby linking love and nature to the dreamworld.