Nov 5 (Reuters) - The debate over U.S. healthcare reform is full of terms familiar to lawmakers and lobbyists but often obscure to the public.

Here is a glossary of words and phrases being bandied about as Congress takes up President Barack Obama's top domestic priority: a bill that reins in healthcare costs, expands coverage to millions of uninsured people and bars insurers from denying coverage for pre-existing conditions or dropping coverage for the sick.

* Bending the cost curve:

U.S. healthcare spending is rising much faster than the general rate of inflation. Lawmakers have no expectation of actually cutting prices. The best they hope for is slowing the rate of growth and thus "bending the cost curve."

* Cadillac health plans:

These are high-cost insurance plans that require little or no out-of-pocket expenses for medical treatment. Many union employees, workers in high-risk professions and corporate executives have them. The Senate bill calls for imposing a tax on such plans, something ardently opposed by unions, which are a key Democratic constituency.

* Cooperatives:

A nonprofit, membership-owned medical insurance plan. Premiums are collected from members to pay for health expenses of the group. The Senate Finance Committee included provisions and start-up money for health cooperatives in its health reform bill. The idea was offered as an alternative to a proposed new government-run health insurance plan that would compete with private insurers. Liberal Democrats say the co-ops would be too weak to compete with private insurers, but the idea has attracted support from centrist Democrats.

* Doughnut hole: