1. A period characterized by an extended lack of rain. My plants are looking all withered thanks to this dry spell we've had recently.

2. A period characterized by a lack of activity. Because I'm going through a dry spell as a freelancer, I'm constantly worried about how I'm going to pay my bills.

3. slang A period during which one has not been able to engage in sexual activity. No, I haven't had sex since I broke up with my girlfriend, OK? I'm just going through a dry spell right now.