By synonym,synonyms of by

Similarities: Both "by" and "through" can be used to indicate the means or method by which something is done. For example, we can say "I got the information by/through asking my teacher" or "The message was sent by/through email". They both express the idea of using a particular way or channel to achieve something.
Differences: "Through" often implies a more detailed or involved process. It gives the sense of going from one end to the other of a particular path, system, or series of steps. For example, "He achieved success through years of hard work" emphasizes the continuous effort and the process over time. "By" is a bit more general and can be used in a wider range of contexts. It might not always carry the same sense of a detailed process. For instance, "The door was opened by the janitor" simply indicates the agent who performed the action without emphasizing the process.

Similarities: "By" and "via" are both used to show the route or means of getting somewhere or doing something. For example, "We traveled to Paris by/via train" or "I sent the package by/via the post office". They are both used to indicate the way or medium through which an action is carried out.
Differences: "Via" is often used more in the context of transportation or communication routes. It is commonly used when referring to a specific path or channel. For example, "The signal is transmitted via satellite" clearly indicates the specific means of transmission. "By" can be used in this context too, but it is more versatile and can be used in other situations like indicating the agent of an action as mentioned before. "Via" is less commonly used in those cases. For example, we wouldn't say "The book was written via the author".

Similarities: In some cases, "by" and "with" can have similar meanings. For example, when indicating the use of an instrument or tool, we can say "The table was cut by/with a saw". They both can be used to show what is used to perform an action.
Differences: "With" is more focused on the accompaniment or the presence of something or someone. It often implies a sense of togetherness or association. For example, "I went to the park with my friends" emphasizes the company. "By" is not used in this sense of accompaniment. When "by" is used with an object, it is more about the means or the agent. Also, "with" can be used to describe having a certain quality or characteristic, like "a man with a lot of knowledge", which is not a usage of "by".

Similarities: In some contexts, "by" and "alongside" can both imply a sense of proximity or being next to something or someone. For example, "The boat was tied by/alongside the dock" shows the position of the boat in relation to the dock.
Differences: "Alongside" specifically emphasizes the side-by-side position. It gives a stronger sense of being parallel and adjacent. "By" is more general and can mean near or next to in a broader sense. "Alongside" is often used when we want to highlight the specific position of two things in relation to each other in a side-by-side manner. For example, "The two cars were parked alongside each other" emphasizes the parallel and adjacent position more than if we just said "by each other".