Like other adventurers, British-born Grenville Boyd uses it to distinguish from magnetic north, the direction in which magnetic compasses point. But his wife sees it as a powerful metaphor for sticking to your core values. "I've used it internally for a number of years and people have picked it up," she said on a short trip to London to speak at a conference on business strategies for the next century.
And she feels it has helped the firm through its turnaround earlier this decade. The situation, which led to the organisation losing nearly half its world-wide staff and seeing revenues fall dramatically from an estimated 1989 peak of $240m, was precipitated by the decision at the end of the 1980s of Bill Bain and seven other founders to leave the organisation they started in 1973 with a large sum of money.
The years 1990 and 1991 saw fierce struggles over the size of that sum, but Ms Gadiesh insists there was never a financial crisis and also acknowledges that the experience has given the firm a useful, if unwelcome, insight into the problems suffered by its clients.
Nevertheless, one senses that she regards the episode as over. Instead, she concentrates on asserting that the firm - whose revenues, in keeping with the status as a partnership, are not disclosed - is growing "faster than anybody else", at between 25 and 40 per cent a year.
The other affair which brought the normally low-profile, somewhat stuffy Bain & Co into the limelight was the Guinness scandal. Thanks to the secondment of the firm's Olivier Roux to assist Ernest Saunders in setting strategy, business people gained the impression of the drinks company being over- run with "Bainies". That, she says, was "clearly a mistake I hope we've learned from".
Indeed, many would see the appointment three years ago of Ms Gadiesh as chairman of the board as an attempt to break with the past.
In an organisation noted for a certain East Coast button-down style and uniformity of outlook, she stands out. Her purple hair, long red finger nails and prominent costume jewellery are much remarked upon. But it is not just her appearance that makes Ms Gadiesh unusual.
True, she attended Harvard Business School before joining Boston-based Bain in 1977. But there the similarity with most of the thousands of people graduating from the world's management schools ends.
The daughter of an Israeli general whose 75th birthday celebrations she attended at the weekend, she did her own turn in the army (in intelligence) before following up her degree in psychology with a teaching position at her alma mater Hebrew University. A year's study leave in the US resulted in her going out with a Harvard Business School student and coming to the view that she should try that line herself.
Though she spoke little English she was accepted for the prestigious course and graduated in the top tier with the Brown prize for the most outstanding marketing student.
She was adamant that she wanted to work in New York or London but was persuaded to stay in Boston by the vision Mr Bain put forward when she asked him during her interview what the firm would be doing in five years. From the beginning, she found that the proposition that Mr Bain had was "unique and fascinating".
She admits that the approach to consulting he adopted on giving up his position as heir apparent at Boston Consulting Group to go out on his own does not sound revolutionary today. But then the idea that a consultant's product should not be a report but bottom-line results for the client revolutionised the industry.
"It called for a different approach to how you work with clients. It's not enough to have a great idea. If it doesn't get implemented or can't get implemented, it's not a Bain product," she says.
This emphasis on implementation is now fashionable, though Ms Gadiesh maintains that few other consultancies are as effective at it as Bain. It means working with people at all levels, rather than concentrating on the executive level favoured by most consultants.
But then she likes to get her sleeves rolled up. As a strategist, she likes to point out that she has not specialised in any particular industry.
None the less, she did spend an early part of her career in steel, where she reportedly retorted to one old hand's remark about women being unlucky by saying: "You should make sure I go to every one of your competitors."
Even now she spends 70 per cent of her time on client work. But that is typical of the Bain management and stems from a belief that it prevents the most experienced people being removed from where they are most valuable - helping clients - and enables them to keep in touch.
But though her working week often approaches 100 hours, Ms Gadiesh, who quotes Oscar Wilde in support of her refusal to state her age, is equally adamant that the broad perspective expected of the strategic consultant requires active interests outside the office.
Though she does not often accompany her boat-mad husband because of seasickness, she is an avid reader of history, fiction and science as well as keen theatre goer. Foreign trips often end with boxes of books being shipped home.
While she admits that the psychology training helps her to spot clients' concerns, she attributes her ability to "read" people to her reading of books. Anthony Powell's A Dance to the Music of Time is especially insightful, she explains.