Morale reflects the training and experience of your military units. Morale levels range from Very Green to Green to Disciplined to Hardened, Veteran, Commando, and Elite. A unit receives a +12.5% combat bonus for each morale level. Morale plays a particularly important role in psi combat, and in combat between probe teams, since no weapon and armor values are considered in those cases.
New units typically begin with Green morale, though this may be higher or lower depending on your social engineering morale setting. A new unit's morale can also be increased if a base has a Command Center or other related facility.
Alien units such as Mind Worms have life cycles which correspond to morale levels. Alien units are not affected by Command Centers and military facilities, but their life cycle levels can be improved by building Biology Labs and other similar facilities. The transport capacity of an Isle of the Deep is determined by its life cycle level: one unit for each level.
A unit victorious in combat will often receive a morale upgrade (the lower its morale level, the more likely an upgrade).
Elite units receive a special bonus--an additional move each turn.
A unit with a ""+"" sign after its morale possesses a combat bonus from its location in a base with a Children's Creche. "