AFAIK I know there isn't any Android specific definition (would welcome corrections from others). Having said that, industry seems to treat this metric differently.
Wikipedia definition implies 100% discharge to count as one cycle, where as industry seems to treat 80% discharge to count as one cycle per sources below
Cycle Life: The capacity of a rechargeable cell or battery changes over its life. The definition of the battery life or cycle life of a battery is number of cycles that a cell or battery can be charged and discharged under specific conditions, before the available capacity falls to a specific performance criteria - normally 80% of the rated capacity
A discharge/charge cycle is commonly understood as the full discharge of a charged battery with subsequent recharge, but this is not always the case. Batteries are seldom fully discharged, and manufacturers often use the 80 percent depth-of-discharge (DoD) formula to rate a battery. This means that only 80 percent of the available energy is delivered and 20 percent remains in reserve. Cycling a battery at less than full discharge increases service life, and manufacturers argue that this is closer to a field representation than a full cycle because batteries are commonly recharged with some spare capacity left.
There is no standard definition as to what constitutes a discharge cycle (....)
To summarise, Wikipedia definition seems academic while industry treats it practically
(Aside, Charge Cycle Counter, which measures battery charge cycles follows Wikipedia definition )
Why I presume Android follows industry definition
Apart from the two reasons mentioned above for 80% discharge to be measured as one cycle (namely, real life charging and better battery life ), I suspect that battery manufactures would prefer this as it boosts battery life cycle count by 20% compared to Apple/Wikipedia definition.