Maricopa Community College District definition: http://www.mcli.dist.maricopa.edu/ocotillo/hybrids/what.php

What is a Hybrid Course? It may not be so useful to aim for a singular definition- hybrid courses likely range across a spectrum of regulary scheduled in class learning to space and time independent online learning. And many things lie between.

A hybrid course is a blend of face-to-face instruction with online learning. In a hybrid course, a significant part of the course learning is online and as a result, the amount of classroom seat-time is reduced.
California State University Long Beach

Austin Community College: Note that online hybrids have 51 per cent of the instruction online.
http://dl.austincc.edu/hybrid/

"Hybrid" is the name commonly used to describe courses that combine traditional face-to-face classroom instruction with online computer-based learning. ACC Hybrid courses combine the best of two worlds, engaging students in the active, autonomous learning process of an Internet-based PCM course, while also providing regularly scheduled interaction with the course instructor.

Arizona State http://asuonline.asu.edu/facultysupport/hybrid.cfm

A hybrid course combines face-to-face instruction and web- or computer-based learning in an educational environment that is non-specific as to time and place. Common features of hybrid courses include the delivery of the syllabus, lectures, readings and assignments on web pages; discussions and presentations through online message boards, e-mail and chat software; interactive tutorials and labs; and on-line assessments (or any combination of the above). In a hybrid class, a significant part of the course interaction takes place online and students can expect to spend at least as much time as they would in an on-campus section of the course.

Durham Technical Community College
http://courses.durhamtech.edu/tlc/www/html/Special_Feature/hybridclasses.htm

Hybrid Courses: The Best of Both Worlds "Hybrid instruction is the single greatest unrecognized trend in higher education today."—Graham Spanier, President of Penn State University Definition:

• Hybrid courses are courses in which significant portions of the learning activities have been moved online, a combination of traditional classroom and Internet instruction.
  
• Time traditionally spent in the classroom is reduced but not eliminated.
  
• The goal of hybrid courses is to join the best features of in-class teaching with the best features of online learning to promote active independent learning and reduce class seat time.
  
• Using computer-based technologies, instructors use the hybrid model to redesign some lecture or lab content into new online learning activities, such as case studies, tutorials, self-testing exercises, simulations, and online group collaborations.

University of Arizona http://sirls.arizona.edu/courses/delivery

Hybrid classes

• Hybrid classes combine face-to-face class meetings with extended participation of projects, often virtual, after the face-to-face meetings. SIRLS hybrid classes meet typically over three weekends, with pre- and post- work depending on the course and the instructor. Most hybrid classes meet in Tucson, with occasional hybrid classes in Phoenix.

Grossmont Community College http://www.gcccd.edu/online/blended_classes.htm

How Blended (Hybrid) Classes Work A blended (hybrid) course is taught partly in the classroom and partly online. Blended courses allow the student to benefit from both methods of teaching: online and face-to-face.