Bottom is a well-meaning but poorly-educated townsperson, a weaver by trade. He is endeavoring to organize a group of others from the town to present the play "Pyramus and Thisby" as an entertainment during the celebrations after the wedding of Thesus and Hippolyta. His particular role for the play-within-the-play is that of Pyramus, the star-crossed lover.
As Bottom and his co-actors rehearse for their play in the woods outside Athens during the night before the wedding festivities, they are discovered by Puck, who has been sent on a mission by Oberon to sprinkle his love potion on Demetrius. Puck anoints Bottom, unknowingly wearing the head of an ass instead of the mask he should be wearing during the rehearsal. The confusion between the intermingled pairs of lovers grows from there.
Bottom is a character intended to add greatly to the comedy of the situation. His choice of words frequently adds to the ridiculous situations in which he finds himself as he gamely strives to accomplish the mission of presenting the play in honor of the royal marriage.