The first meaning that comes to mind for the word is “error”. Fault in the source code that can lead to both errors in the program solutions and completely unexpected behavior. In this context of inexplicable errors, in Portuguese, there is not even a precise translation. It's a bug anyway.
In English, the first suggested translation is “insect”, even though there is also the meaning of “defect”. Interestingly, this first understanding keeps alive the memory that bugs also exist in hardware. And that was its origin there, probably with a real insect causing reading problems in Thomas Edison's phonograph, in 1878. That's what they say, without much guarantee, although it is certain that the term was already used long before the arrival of the computer, in the sense of mechanical failure.
When the problem really is a failure in the program's logic, what justifies it is the great complexity of the source codes. Corte Certo, for example, has hundreds of thousands of files, each with hundreds of lines of code. As much as auxiliary control methods and tools have evolved, it is still impossible for the human mind to maintain absolute control over such an extensive field of intervention. That's why in the license agreement for any software the developer is exempt from liability in the event of bugs.
This care is more than necessary because, above all, the bug can be caused by unwanted external interference from other systems, such as Windows, malware or even antiviruses with their false positives.
From there you can already get an idea of the difficulty that programmers have in discovering the origin of a reported bug. It's often worse than finding a needle in a haystack.
Finding the problem that generates the bug is essential to solving the problem, but it is not a guarantee that the solution will be found. The best example of this was the famousMillennium Bug, at the turn of the year 1999 to 2000. From a simple computing problem it created end of the world atmosphere, with the invasion of American supermarkets to build up food stocks. In the foreshadowed apocalypse, a huge disorder in the world economic system would lead millions of companies to bankruptcy. Financial investments could have negative values, causing a wave of suicides. Dangerous bandits would be released, planes would crash, countless industries would shut down. And all because, in the last century, only two digits were used for the position of the year in the date fields of software – so the year 2000 could be understood as 1900, making the computer go crazy.
In the end the catastrophe did not come.
For 2038 there is a similar problem predicted. The affected software are those that calculate the date using the number of seconds, ignoring leap years. As far as Corte Certo is concerned, its users can sleep easy, as this is not the case.