Dictionary.app to console output.

dict.m

/* clang -fobjc-arc -framework Foundation -framework CoreServices dict.m -o dict */

#import <Foundation/Foundation.h>
#import <CoreServices/CoreServices.h>

int main(int argc, const char * argv[])
{
    @autoreleasepool {       
        if(argc < 2)
        {
            printf("Usage: dict <word to define>\n");
            return -1;
        }
        
        NSString *search = [NSString stringWithCString: argv[1] encoding: NSUTF8StringEncoding];
        
        CFStringRef def = DCSCopyTextDefinition(NULL, (__bridge CFStringRef)search, CFRangeMake(0, [search length]));
        NSString * output = [NSString stringWithFormat: @"Definition of <%@>:%@", search, (__bridge NSString *)def];
        
        printf("%s", [output UTF8String]);        
    }
    return 0;
}