Type the word 'bocka' into a search engine and you'll get a variety of results ranging from the act of bending or bowing, to a municipal district in Germany.

But in Ballarat, 'bocka' means 'haircut' and it seems no-one knows why.

Bocka (also spelt bocker, depending on who you ask) is a colloquialism in the regional Victorian city, yet despite its relative commonality among locals, the story behind its origin is based on inter-generational rumour.

Geoff Johnson is a barber in Ballarat's CBD and has been trimming bockas for 38 years.

"It's not bad … you only get 12 years for murder in Australia," he says.

Where does the bocka come from?

Bocka is a term that Geoff said was once regularly used among locals, but now seems to be lost on customers under the age of 30.

"Nowadays it's all about the new trends like 'I'll have a fade, thanks', which is in at the moment," he says.

"In 1927 that was in fashion, it's just come back again."

Geoff says he's had a wide variety of people come through his barbershop doors over the years, and he's even negotiated real estate deals from behind the chair.

Despite picking up little bits of knowledge from his customers, even Geoff has struggled to find a concrete explanation for the bocka's origin.

"I was told yesterday it comes from knickerbockers which the girls and also some golfers wore," he said.

"So short pants, and then it went from short pants to short haircuts."

A little bit of Aussie slang being lost

Barber Walter Burtt says he began hearing the term 'bocka' as a reference to haircuts when he moved to Ballarat more than 25 years ago. ( ABC Ballarat: Dominic Cansdale )

Across town at his Brown Hill barbershop, Walter Burtt has been doing bockas for 25 years, after moving to Ballarat from the United States.

"Only the older guys know [what bocka means]," Walter says.

"Young people don't use it anymore, they're picking up American slang. … so all the old Australian slang is disappearing, you never hear of 'stone the crows' or 'strewth' or 'beyond the black stump' anymore.

"I like Australia because of its individuality and all the different language but, with computers and the internet now, everything is becoming Americanised or globalised or whatever you want to call it."

In Walter's small barbershop, half a dozen older men have been patiently waiting their turn for the classic 'short back and sides'.

One of them, Rob, said his father talked about 'the bocka' when he was growing up around 50 years ago.

"I don't know where it's come from, but I've heard of it," Rob said.

"Probably at school, sometimes you'd say 'gonna go and have a bocka'."

Fear not, Aussie slang isn't dying — it's changing

Professor of Linguistics at Monash University, Kate Burridge, says concerns that Aussie slang is going the way of the dodo are misguided, with terms like bocka instead changing over time.

"It's a fact of lexical life that words will wear out and slang is more short-lived," she says.

"It has to be because for something to be slangy, it's got to be new, it's got to attract attention."

While Professor Burridge says she is not aware of bocka or its origins, most slang words have common features that "fulfil a need" and make them popular.

"It catches people's imagination and they dream up these stories and I'm sure that helps propel them along this successful route," she says.

"Sometimes celebrity endorsement gives them some help … if you think of something like 'twerk', that was around in the 1990s but no-one paid it much attention until Miley Cyrus.

"Even with Shakespeare … he had a fabulous ear for slang, the verb for dog from the noun dog, taking a noun and turning it into a verb, he sort of made that popular."

Professor Burridge says as slang changes, so too will the way it is used with the internet giving slang a new platform to spread.

"Shortening is a big part of slang — whether you turn it into an acronym, a pronounceable thing like 'lol'," she says.

"What makes that handful survive? Well, they have to fill a need."