Redwood generally refers to one of several species of tree with red or reddish colored wood:

Sequoiadendron giganteum - Giant Sequoia or Sierra Redwood

Redwood City, California

Family Fabaceae (broadleaf)

Sequoia sempervirens - Coast Redwood

Muir Woods National Monument -- old-growth redwood park in California, sometimes meant when referring to "the redwoods" in California.

Family Cupressaceae (conifers)

Redwood Falls, Minnesota

Redwood County, Minnesota

Metasequoia glyptostroboides - Dawn Redwood

Caesalpinia echinata - South American Redwood, or Brazilwood tree

Cryptomeria japonica - Sugi

Redwood, New York

Family Pinaceae (conifers)

Redwood, Oregon

Family Sterculiaceae (broadleaf)

Redwood Falls Township, Minnesota

Redwood, Texas

Redwood Software

Redwood, New Zealand

Redwood Shores, California

Caesalpinia sappan - East Indian Redwood, or Sapanwood tree (first called "brezel wood" in Europe)

Redwood Technologies

Trochetiopsis erythroxylon - St Helena Redwood

Redwood Games

Redwood (band)

The wood of Scots Pine (Pinus sylvestris) is sometimes called 'redwood' in the timber trade.

The Redwood Empire (also Redwood Coast or North Coast) is a region of California that stretches from San Francisco to the Oregon coast.

Redwood National and State Parks, National Park in California

Redwood is also the callsign for Virgin America