A nip, a toot, a tot, a half, a wee one – all are used when asking for a measure of whisky in a Scottish pub, and all are widely held to be too small.

But now there is a push to make a dram the official term for a whisky.

It is being led by the organisers of the Spirit of Speyside Whisky Festival, which is held next month.

The organisers contacted the National Measurement Office to ask for the dram to be reintroduced as a measurement so that people could legally ask to be served a dram.

Before the country went metric, most measures of whisky were one-fifth of a gill or one fluid ounce, although some pubs took great pride in serving the larger and older quarter-gill. Now the normal measure is 25ml, which is smaller than the 28.4ml that was the fifth of a gill.

Festival manager Mary Hemsworth said: "The National Measurement Office appears set on the prescribed limit of 25ml and 35ml, so we feel that the only way forward is to press to have these measures officially named a dram – and a large dram – so long as they are used exclusively for the sale of Scotch whisky in Scotland."

She said if it was possible to sell bananas in pounds and ounces, surely they could allow the Scotch whisky industry to sell whisky in drams.

"Even since the introduction of the metric system, beer and cider continues to be sold in pints, so we strongly believe there is a case for parity for Scotch whisky and for it to have its own unit of measurement," Ms Hemsworth said.

"It seems silly that Scotland's other iconic food and drink products such as haggis and shortbread can be sold in weights other than metric, but the same rules do not apply to the most iconic of all Scotland's products."

She said that it was an important stance for whisky in Scotland as the very word dram has conjured up images of warmth and hospitality.

However, it is a campaign which is confusing many drinkers as the term dram is still frequently used today, although there has never been an official dram measurement.

Danny Rogan, bar manager of the Royal Hotel in Cromarty on the Black Isle, said: "When locals come in and ask for a whisky, they will ask for a dram and always have done. They will get a 25ml measure and if they ask for a large dram they will get two measures of 25ml."

Rosemary Gallagher, Scotch Whisky Association communications officer, said a dram had never been a specific measure.

She said: "At our Scotch Whisky: From Grain to Glass centenary exhibition we held last year at the Scottish Parliament, one of our facts explained that a 'wee dram' is not a standard size." But she said there was nothing to stop people requesting a dram.

Paul Waterson, chief executive of the Scottish Licensed Trade Association, which has 1000 members, agreed. "A dram is certainly still widely used for a measure of a single whisky, along with other terms. I think there is a romance about these names and they are worth keeping. They certainly appeal to visitors from abroad."

The word dram has several origins, from the old French dragme, from late Latin dragma, and from the Greek drakhm.