The term refers to a distinctive style of townhouse characterised by a stepped or curved gable end facing the street, a form that was common in Dutch and Flemish cities and was transplanted into Irish urban building during the late seventeenth and early eighteenth centuries. These gabled facades were once a familiar feature of Dublin's streetscape, but so many have been demolished or altered beyond recognition over the centuries that surviving examples, or even credible identifications of them, have become genuinely rare.

The identification of House No. 3 as a Dutch Billy comes from the Dublin Environmental Inventory, compiled by the Department of Architecture at University College Dublin, with the citation tracing back to Maurice Craig's 1969 survey of Dublin's architectural history. Craig was one of the foremost scholars of Irish Georgian and early modern architecture, and his work remains a foundational reference for anyone trying to unpick the layered building history of the capital. The Dutch Billy style takes its popular name from King William III, William of Orange, under whose reign this manner of building became fashionable in Ireland, though the form itself predates him and has deeper roots in northern European mercantile architecture. The stepped gable was partly practical, allowing access to upper floors for hoisting goods, and partly a matter of civic display.

Because the date of the house is listed as indeterminate, it sits in that ambiguous space where architectural typology has to do the work that documentary evidence cannot. Visitors with an interest in early Dublin building should look carefully at the roofline and upper facade when approaching the property, since the defining feature of a Dutch Billy is most legible from across the street rather than close up. The south city retains pockets of pre-Georgian and early Georgian fabric that tend to be overlooked in favour of the grander set pieces around Merrion Square and St Stephen's Green, and House No. 3 is the kind of detail that rewards the slower, more attentive kind of urban walking.