1. to inject a drug directly into a vein
Usage: slang; drug-related

1. relating to a principal railway line
2. representing the most widely accepted beliefs or practices

1. a principal railway line

Examples

• The mainline train service connects major cities across the country.
• She preferred mainline Protestant denominations over smaller sects.
• The freight train traveled along the mainline route.
• His views align with mainline conservative thinking.
• The mainline carries most of the railway traffic in this region.
• They built a new station on the mainline to serve the growing suburb.