Nouns with the same singular and plural forms
Certain nouns have an identical singular and plural form. Some of these nouns end in -s: means, series, species.
The bicycle is a means of transport.
The five human senses are our means of communication with the material world.
A series of burglaries has been going on around the neighbourhood.
What are your favourite TV series?
A new species of bird has been discovered in Indonesia recently.
Since the 17th century, more than 500 marine species have become extinct in the US.
Other examples are:
aircraft
deer, sheep
fish, carp, pike, salmon, trout
