expectancy

As an adjective expectant

is marked by expectation.

As a noun expectancy is

expectation or anticipation; the state of expecting something.

As nouns the difference between expectancy and expectance

is that expectancy is expectation or anticipation; the state of expecting something while expectance is anticipation, hope.

As nouns the difference between forecast and expectancy

is that forecast is an estimation of a future condition while expectancy is expectation or anticipation; the state of expecting something.

As a verb forecast

is to estimate how something will be in the future.

As nouns the difference between taxonomy and expectancy

is that taxonomy is the science or the technique used to make a classification while expectancy is expectation or anticipation; the state of expecting something.