oak
occupational hazard
occupational risk
occupational safety
odour
offspring
oil
oilborne preservative
olive
opacity
open field
operation
operator
opposite
opposite branching pattern
orbital sander
order
organ
organic
organisational factor
oriented strandboard (OSB)
origin
ornamental
outdoor furniture
outer bark
outermost
outline
ovate
oxidation
oxidative
oxidize, v.
oxygen
