The most common meaning of "zahf" in Arabic is "crawling," but it can also mean "marching" as in protesting in the streets with many people or walking like a soldier. "March Friday" has nothing to do with the act of crawling in this context.

جمعة الزحف من أجل مصر جمعة = Friday الزحف, remember if you want to understand a word in Arabic, we do a way totally different from English, as you know when you misunderstood a word in English you go to the dictionary to find it. In Arabic, as we have a lot of words " Arabic has a large vocabulary we need a strategy to use". We usually come back the verb origin to find the meaning. الزحف is coming from the verb : َيَزْحَفَ زَحَف which means creep or crawl in English, so action of the verb is the meaning of الزحف (crawling) من أجل = for مصر = Egypt. Now, no need to explain the meaning of. It's too clear for you now :). Just remember as I was saying before, it's more useful to use dictionary to understand the words as well as you understand yours in your language.

Literally it means the Friday of crawl but it means in Friday we will (protest-fight-walk) with huge numbers any way in this situation means going to a place with huge number and this is happening in Egypt today i know

Now that these respected fellows explained the word litterally, what you need to know is that the word الزحف is meant here by a huge number of people (walking) along to a destination, creating a formed organized unit (from above seen as something crawling as it moves slowly)!

الزحف = walking , marching , جمعة = Friday