I would like to know on the center gauge left side of the landing Gear stick the word .fmc comes up on the gauge,would like know the meaning of this.

It means there is some unfinished task in the FMC, mostly the wind data on the legs page or something on the perf page isn´t complete.

It´s the FMCs way to tell you it needs some attention😉 

This ".FMC" message is classed as a medium level EICAS alert and is generated when the aircraft receives a datalink communication message (ACARS). The message's title will be visible in the CDU sctratchpad and to view the message just select the appropriate CDU page or push the FMC COMM key. 

The message you are most likely to see when the FMC is saying it needs some attention is  ">FMC MESSAGE".