Caching
Calendar or a marketing calendar
Call to Action (CTA)
Campaign
Campaign Latency Period
Capping
CDN (Content Delivery System)
Certified Partner
Click
Click Through
Click Through Rate (CTR)
Cohort
Comment Spam
Complete Navigation
Completion Rate
Contact Rate
Content Management System (CMS)
Content Marketing
Contextual Advertising
Conversion
Conversion Rate
Cookie
CPA (Cost Per Action)
CPC (Cost Per Click)
CPL (Cost Per Lead)
CPM
CRM (Customer Relationship Management)
Cross-Border Processing
Cross-Channel
CSS (Cascading Style Sheets)
Custom Variables
Customer Acquisition Cost
Customer Centric