The two crossword solutions for the term 'make airtight, in a way' are CAULK (5 letters) and heatseal (8 letters). Caulking is a process of sealing cracks or gaps in surfaces by filling them with a flexible material such as silicone, which hardens over time. Heatsealing is a process of joining two materials together by applying heat and pressure. It is commonly used to seal plastic bags and other packaging materials. Both processes are used to make surfaces airtight and prevent air or moisture from entering.