"Plastic" has been declared children's word of the year after analysis of the stories submitted by five to 13-year-olds in a writing competition.
Oxford University Press examined the words used in stories sent to BBC Radio 2 Breakfast Show's 500 Words contest.
'Plastic' appeared 3,359 times in the 134,790 stories submitted - up 100% from last year.
Unicorns, slime and the computer game Fortnite were among the other subjects that influenced children's language.
David Attenborough's Blue Planet II programme is credited with influencing children's writing, with titles such as The Plastic Shore and The Evil Mr Plastic, being sent in.
The use of the terms recycle and recycling also increased, along with packaging, pollution, plastic bottle, plastic bag, and plastic waste.
Vineeta Gupta, head of children's dictionaries at Oxford University Press, said: "Children have shown they are acutely aware of the impact plastic has on our environment and how it will affect their own future."
The use of the word "game" increased by 66% in the 2018 competition, up from 17,000 to 30,000 mentions.
Gaming-related words such as console and noob - an inexperienced player - also increased.
Boys aged five to nine were said to engage most with the vocabulary of gaming.
Mentions of gaming as an addiction and adults who cannot stop using social media also appeared in stories.
The use of the word "Brexit" increased, but was mainly mentioned as an item on the news or as a boring topic of conversation.
Other popular words
- Donald Trump
- Cristiano Ronaldo
- Grenfell Tower
Trump was the children's word of the year in 2017. The US President remains the number one real life figure mentioned in stories, ahead of his nearest rival, the footballer Cristiano Ronaldo.
The winners of 500 Words writing competition for children aged 5-13 will be announced on Friday.