EMS

1. Emergency Medical Service
2. Enhanced Messaging (or Message) Service (for mobile phones)
3. European Monetary System
4. Expanded memory system (computing)

em /em/

1. The thirteenth letter of the modern English alphabet (M or m)
2. A unit of measurement (equal to the width of the lower-case letter ‘m’ in 12-point) used in spacing material and in estimating dimensions of pages (printing)

em dash or em rule noun (printing)

A dash that is one em long, used as a punctuation mark

• will-lessly
• will-lessness
• will-o'-the-wisp
• will-o'-the-wisps
• willow
• willowed
• willow grouse
• willowherb
• willowherbs
• willowier
• wave mechanics
• wavemeter
• wavemeters
• wave motion
• wave motions
• wave number
• wave numbers
• wave off
• wave offering
• wave offerings
• wave-particle duality
• wave power
• waver
• wavered
• waverer