1. gaps, holes, or spaces that allow passage or access
2. available job positions or opportunities
3. beginning parts or introductory sections

Examples

• The cave had several openings that led to different chambers.
• There are three job openings in the marketing department.
• The company posted new openings on their website yesterday.
• The openings of both novels were quite compelling.
• We attended the gallery openings for two new art exhibitions.
• Small openings in the fence allowed rabbits to enter the garden.
• The theater openings this season feature several Broadway shows.