Disclaimer: 2D Compasses or Linear scales are generalizations and there's much more things at stake than what they represent. Like this:
The idea of Liberal = Left exists almost solely in the context of the USA, due to the internal drifting factors of political ideology at the beginning of the 20th century.
The basic political compass taken in count in almost every country to define what a party or a person is are State Power and citizen freedom (from Anarchic to Authoritarian) and State Econo-Social status (From Libertarian to Conservative).
A well explained example is that, although the United Kingdom's LibDem party is considered a economically speaking Libertarian party (a small state where private enterprise is highly promoted and taxes are low on most scales), socially speaking, it's center-to-right leaning with many conservative and authoritarian policies when you see their parliamentary voting preferences. That makes it a economically Libertarian (or Liberal, as most of Europe says), Socially authoritarian party.
An American listening to the term "Liberal Democratic party" without prior knowledge of UK politics would expect, instead, a economically restrictive, left leaning social party.
Uk compass of parties after the 2015 elections
If we made a political compass of the main United States parties, we would find out that both the Democratic Party and the Republican Party support similar ideas since late 1920's, with only the means of execution and cherry picked end results being the distorting note.
Oversimplified example: like Obamacare vs Trumpcare, Both just a small patch with not many big-scale differences over a titanic privately run for profit healthcare system.
Given that, the parties and their members had to find a way to distinguish themselves. The term Liberal has changed its coinage from its origins just like most 19th-century-born ideologies, and is usually mixed with Neoliberalism (Thatcherism), a globalized, right-leaning and extreme version of it that rose in popularity during the Reagan and Thatcher eras (late 1970's until mid 1980's).
The current meaning of Liberal in the US is often associated with a milder, soft, more tax-prone, more social spending and more corporate brand of American Conservadurism, whereas Conservative is often associated with a more socially strict, less tax stagnant, more decentralized to the states and more Nepotic brand of American Conservadurism.
The terms Left-leaning and Liberal, hereby, should only we interchangeable in USA's own interpretation on what Left, Right, Libertarianism, Liberalism, Authoritarianism and Conservadurism mean, different from mainland Europe, Uk, Africa, or Asia, just like the same terms in Europe would be different than on Asia ( except, maybe, on ex-colonies).
Finally, and to illustrate how diverse and different is the political "compass" around the world, I'm a citizen of Spain, and I favour a center-left social democrat republican party, not even near extreme left, Libertarian leaning. Me (and my party) are considered as part of the "Left" blob of Spanish parties, to the Left of the centrist Socialist Party (the name is misleading), and to the right and below the populist and extreme-left parties.
This is my compass:
Compared to the US compass, I'm almost an Anarchist, compared to the UK compass, I'm less libertarian than a Green, but slightly more lefty. Compared to a French political compass, I'm as Lefty as Melenchon but way more libertarian.