Also found in: Dictionary, Thesaurus, Encyclopedia. Slack is a channel-based messaging platform. With Slack, people can work together more effectively, connect all their software tools and services and find the information that they need to do their best work – all within a secure, enterprise-grade environment. Channels in Slack Discover a new way of working. To decrease in activity or intensity.

| Slack | |
|---|---|
| Native name | La Slack(French) |
| Location | |
| Country | France |
| Physical characteristics | |
| Source | |
| • location | Pas-de-Calais |
| Mouth | |
• location | English Channel |
| 50°48′18″N1°36′5″E / 50.80500°N 1.60139°ECoordinates: 50°48′18″N1°36′5″E / 50.80500°N 1.60139°E | |
| Length | 22 km (14 mi) |
The Slack (French pronunciation: [slak], in Picardlocally [s̟laːk]) is a 22-kilometre-long (14 mi) coastal river in the Pas-de-Calais department, in northern France.[1]
It rises at Hermelinghen on Mount Binôt, flows through Rinxent, Marquise, Beuvrequen, Slack (village near Ambleteuse) and flows into the English Channel in Ambleteuse next to Fort Mahon.
| Wikimedia Commons has media related to Slack River. |
